[OMPT] Add OMPT events for API locking

This fix implements the following OMPT events for the API locking routines:

• ompt_event_acquired_lock
• ompt_event_acquired_nest_lock_first
• ompt_event_acquired_nest_lock_next
• ompt_event_init_lock
• ompt_event_init_nest_lock
• ompt_event_destroy_lock
• ompt_event_destroy_nest_lock

For the acquired events the depths of the locks ist required, so a return value
was added similiar to the return values we already have for the release lock
routines.

Patch by Tim Cramer

Differential Revision: http://reviews.llvm.org/D13689