Tests and Sample variables are making dangerous assumptions

[franck-boullier]

The problem:

The files main_test.go and tests/sample.json are assuming that there is:

• an existing user in the installation with the BzUserId = 55
• an existing Classification in the BZ installation with classificationId = 2

This might not always be true.

The fix:

• In the BZ seed script when we create a BZ installation from scratch, we need to create a specific user for tests.
• This repo should use this specifically created user for tests.

[franck-boullier]

One consequence of this issue seems to be that the build on Pushed branches from Travis CI will always fail.
The temporary fix is to configure Travis CI to build only on PR.