osc/rdma: fix bugs in lock_all and flush_all

This commit fixes two bugs:

 - We were not correctly setting the lock type in the outstanding lock
   for lock_all. This caused undefined behavior.

 - flush_all was incorrectly checking for comm size - 1 lock acks but
   comm size flush acks. This is the reverse of what was intended.

cmr=v1.8:reviewer=jsquyres