Fix: student cannot resign with his enrollment
Fix: student cannot resign with his enrollment

Student cannot resign with his enrollment if the subject he enrolled
has fulfilled maximum amount of enrollments

Change-Id: I11d69da1812e18a62e2e02127371bb756a96aab2

Opensoftware/USI-Graphite,Opensoftware/USI-Graphite,Opensoftware/USI-Graphite