Mapping engine does not handle regex properly

Currently, if there is more than one assertion value (the list of
group ids returned from the idp). Then when using regex to compare
again the mapping values, only the first values are used.

Change-Id: Iba7d455ef0d5fc2d4ac16f4a7eb553845270fb2c
Closes-Bug: #1321536
Merge "Mapping engine does not handle regex properly"