OSHMEM: spml ikrit: complete puts b4 memheap destruction

Force completion of all puts before deregestering memheap/bss memory

Fixes a possible race condition where put request completion callback
is called when request context is already cleared.

Change-Id: I7ed887ec0b03a66ce5d3076a7edcf64061f57370
(cherry picked from commit 5af4d02bd3b601a18f6fb03b1837fceb6534261e)
Merge pull request #35 from alex-mikheev/topic/oshmem_spml_ikrit_race-v1.8

OSHMEM: spml ikrit: complete puts b4 memheap destruction