Python check unification

[sbesson]

While reviewing the phases executed on CLI plugins, I realized that the Python quality tools like flake8 are currently not executed.

The changes of this PR are the following:

• adding py-check to the CLI entrypoint so that all OMERO CLI plugins are validated by flake8 when executing cli-docker /cc @dominikl
• unifying py-common and py-update which seem to be doing the same apart from 1- pip install --upgrade pip which has all kind of caveats as we saw recently, 2- pip install requirements.txt which is necessary for installing flake8
• expand cli-build test scope to run all tests under test/integration

Searching https://github.com/search?p=2&q=user%3Aome+user%3Aopenmicroscopy+omero-test-infra+filename%3A.travis.yml&type=Code, there are currently 4 repos which might be affected by the changes of the cli and script phases:

• ome/scripts CI is unmodified by this change - see https://travis-ci.org/sbesson/scripts/builds/414110835
• ome/omero-cli-duplicate CI is unmodified by this change - see https://travis-ci.org/sbesson/omero-cli-duplicate/builds/414111412
• ome/omero-cli-render#12 fixes omero-cli-render to be flake8 compliant
• ome/omero-metadata#4 fixes omero-metadata to be flake8 compliant and execute all integration tests

Proposed tag: 0.3.6

[joshmoore]

I'll be surprised if this passes all the repos, but if it doesn't, happy to look into alternative (pinning?) solutions.

[sbesson]

So far, I have the following behavior:

• ome/scripts is unaffected - see https://travis-ci.org/sbesson/scripts/builds/414110835
• ome/omero-cli-duplicate is also unaffected - see https://travis-ci.org/sbesson/omero-cli-duplicate/builds/414111412
• ome/omero-cli-render has a few flake8 issues - should be covered by https://github.com/ome/omero-cli-render/pull/12
• ome/omero-metadata has also flake8 issues - working on it.

Any other downstream repo you can think of?

[joshmoore]

Seems to match: https://github.com/search?q=org%3Aome+%22cli-docker%22&type=Code

[sbesson]

As discussed with @joshmoore and @jburel, 774f1da pushed to expand the test scope of cli-build. PR description updated and all integration branches have been relaunched to account for the changes.