Backport Havana: excercices: aggregates needs to be more flexible

The actual regex checks a result in python format and
because of the change in the bug 1132961, Jekins failed.

I have update the regex to work with the old result
and the new result.

    From: 75e851a

Change-Id: Idb23ddd32f7f7bf0eeecba9794c705365e3b2122
Closes-Bug: 1239726