LocalBearTestHelper: Decommission timeout
LocalBearTestHelper: Decommission timeout

LocalBearTestHelper had an undeclared dependency on pytest-timeout
so it would not work unless the user had install pytest-timeout.
Only one of our bear test suites use this timeout argument, as the
timeout set in the repo configuration is typically sufficient.

Fixes https://github.com/coala/coala/issues/5508

SanketDG/coala,jayvdb/coala,coala/coala,SanketDG/coala,coala/coala,coala-analyzer/coala,coala/coala,SanketDG/coala,jayvdb/coala,jayvdb/coala,coala-analyzer/coala,coala-analyzer/coala