fix unset global variable in BaseLanguageFactoryTest

Change-Id: Id729a9bd4fc45ae5dcf43665da65883817dadc0b
Merge commit 'refs/changes/92/2292/1' of ssh://gerrit.tuleap.net:29418/tuleap into stable

* ssh://gerrit.tuleap.net:29418/tuleap:
  fix unset global variable in BaseLanguageFactoryTest
This is Tuleap 6.12.99.50

Change-Id: I6e9f311c1105f9aaaa77b94a1eeb3847fbfd4c6e