added a check for oid and name to prevent empty metrics

[MyaLongmire]

Required for all PRs:

• Updated associated README.md.
• Wrote appropriate unit tests.

resolves #8840 SNMP input can produce metrics with empty metric name

Added a check for empty oid and empty name
fixed an existing unit test to give the table a name
and added a test for a table with empty oid and empty name

[telegraf-tiger]

Looks like new artifacts were built from this PR. Get them here!

Artifact URLs

• windows_amd64.zip

• windows_i386.zip

• darwin_amd64.tar.gz

• x86_64.rpm

• freebsd_amd64.tar.gz

• linux_amd64.tar.gz

• amd64.deb

• linux_mipsel.tar.gz

• mipsel.deb

• s390x.rpm

• linux_s390x.tar.gz

• s390x.deb

• linux_mips.tar.gz

• mips.deb

• armv6hl.rpm

• freebsd_armv7.tar.gz

• linux_armhf.tar.gz

• armhf.deb

• ppc64le.rpm

• linux_ppc64le.tar.gz

• ppc64el.deb

• armel.rpm

• linux_armel.tar.gz

• armel.deb

• static_linux_amd64.tar.gz

• i386.rpm

• freebsd_i386.tar.gz

• linux_i386.tar.gz

• i386.deb

• aarch64.rpm

• linux_arm64.tar.gz

• arm64.deb

[Hipska]

Did this pass all tests? Cause it makes telegraf to crash when you use ifName processor!

[Hipska]

It did pass the tests, more disturbing is that the specific ifname test has been disabled in #8725 😱