fix(components): Disable cache_discovery in GCP component.

[chensun]

This can fix the import error seen in post-submit tests (once released the container image).

sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	WARNING:googleapiclient.discovery_cache:file_cache is unavailable when using oauth2client >= 4.0.0 or google-auth
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	Traceback (most recent call last):
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	  File "/usr/local/lib/python3.7/site-packages/googleapiclient/discovery_cache/__init__.py", line 36, in autodetect
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	    from google.appengine.api import memcache
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	ModuleNotFoundError: No module named 'google.appengine'
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	During handling of the above exception, another exception occurred:
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	Traceback (most recent call last):
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	  File "/usr/local/lib/python3.7/site-packages/googleapiclient/discovery_cache/file_cache.py", line 33, in <module>
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	    from oauth2client.contrib.locked_file import LockedFile
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	ModuleNotFoundError: No module named 'oauth2client.contrib.locked_file'
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	During handling of the above exception, another exception occurred:
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	Traceback (most recent call last):
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	  File "/usr/local/lib/python3.7/site-packages/googleapiclient/discovery_cache/file_cache.py", line 37, in <module>
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	    from oauth2client.locked_file import LockedFile
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	ModuleNotFoundError: No module named 'oauth2client.locked_file'
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	During handling of the above exception, another exception occurred:
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	Traceback (most recent call last):
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	  File "/usr/local/lib/python3.7/site-packages/googleapiclient/discovery_cache/__init__.py", line 41, in autodetect
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	    from . import file_cache
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	  File "/usr/local/lib/python3.7/site-packages/googleapiclient/discovery_cache/file_cache.py", line 41, in <module>
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	    'file_cache is unavailable when using oauth2client >= 4.0.0 or google-auth')
sample-test-khpbv-717493055: xgboost-trainer-74ttn.onExit:	ImportError: file_cache is unavailable when using oauth2client >= 4.0.0 or google-auth

Fixing part of #5007

[numerology]

/lgtm
/approve

Thanks!

[k8s-ci-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chensun, numerology

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• components/gcp/container/component_sdk/OWNERS [numerology]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[google-oss-robot]

[APPROVALNOTIFIER] This PR is APPROVED

This pull-request has been approved by: chensun, numerology

The full list of commands accepted by this bot can be found here.

The pull request process is described here

Needs approval from an approver in each of these files:

• components/gcp/container/component_sdk/OWNERS [numerology]

Approvers can indicate their approval by writing /approve in a comment
Approvers can cancel approval by writing /approve cancel in a comment

[google-oss-robot]

@chensun: The following test failed, say /retest to rerun all failed tests:

Test name	Commit	Details	Rerun command
kubeflow-pipelines-tfx-python36	50e5762	link	/test kubeflow-pipelines-tfx-python36

Instructions for interacting with me using PR comments are available here. If you have questions or suggestions related to my behavior, please file an issue against the kubernetes/test-infra repository. I understand the commands that are listed here.

[chensun]

kubeflow-pipelines-tfx-python36 failures has nothing to do with this PR, and it tracked by #5049.

Ignoring the failure and submitting.