Merge pull request #4395 from edx/mvo/unittests_alone

Setting default system to be lms in unittests

pavelib/tests.py

@@ -48,6 +48,8 @@ def test_system(options):
     if test_id:
         if not system:
             system = test_id.split('/')[0]
+        if system == 'common':
+            system = 'lms'
         opts['test_id'] = test_id
 
     if test_id or system: