log macro fails in pre/post-hook without the select 1 workaround

[robert-howley-zocdoc]

Issue

Issue description

The log macro cause the model evaluation to fail when executed in a model level pre/post-hook unless the select 1 hack is applied.

Here is the relevant snippet from the dbt_project.yml

# no problem here
on-run-start: "{{ log('project level: pre-hook', True) }}"
on-run-end: "{{ log('project level: post-hook', True) }}"

models:
  # fails
  # pre-hook: "{{ log('models level: pre-hook', True) }}"
  # post-hook: "{{ log('models level: post-hook', True) }}"

  # works
  pre-hook: "{{ log('models level: pre-hook', True) }} select 1"
  post-hook: "{{ log('models level: post-hook', True) }} select 1"

Results

What happened?

Without the select 1 workaround I get the following ...

Found 3 operations, 91 macros, 0 analyses, 0 seed files, 0 tests, 1 models, 0 archives

project level: pre-hook
16:23:32 | Concurrency: 1 threads (target='prod')
16:23:32 | 
16:23:32 | 1 of 1 START view model experimental.my_first_dbt_model.............. [RUN]
models level: pre-hook
16:23:33 | 1 of 1 ERROR creating view model experimental.my_first_dbt_model..... [ERROR in 0.86s]
project level: post-hook
16:23:33 | 
16:23:33 | Finished running 1 view models in 1.17s.

Completed with 1 errors:

Database Error in model my_first_dbt_model (models/example/my_first_dbt_model.sql)
  can't execute an empty query
  compiled SQL at target/compiled/my_new_package/example/my_first_dbt_model.sql

Done. PASS=0 ERROR=1 SKIP=0 TOTAL=1

What did you expect to happen?

Expected the view to be successfully created with models level: pre-hook to be printed before the view creation and models level: post-hook after.

System information

The output of dbt --version:

installed version: 0.11.1
   latest version: 0.11.1

Up to date!

The operating system you're running on: mac sierra

The python version you're using (probably the output of python --version) 2.7

Steps to reproduce

Add the above dbt_project.yml snippet to the sample project autogenerated by db init and connect to redshift.