core: Remove GetNotificationEventMap

GetNotificationEventMapQuery is not used anywhere in
the code, and hence should be removed.

This patch removes the following:
1. The GetNotificationEventMapQuery class.
2. The GetNotificationEventMap constant representing
   it in VdcQueryType.
3. The getAllEventMaps() method in EvetDAO, its
   implementation, test and underlying stored procedure, as this
   method was only used by the aforementioned query.

Change-Id: Icfb382d6d294ac4ce940646cc0ef33f35d9e10cc
Signed-off-by: Allon Mureinik <amureini@redhat.com>