Use oslo tests fixture

Change-Id: I3f60381bebfcad0ba5b597276bac5fd62213470c
Use correct name of oslo debugger script

As of oslotest 1.2.0 the oslo debugger script dropped the .sh
extension. This patch corrects the use the script name in tox.ini

Change-Id: I0b814f5136e2858ac53ba45db523790d220a6b88
Merge "Use correct name of oslo debugger script"