Fix the bug in rev. 1.134. In devfs_allocv_drop_refs(), when not_found == 2 and drop_dm_lock is true, no unlocking shall be attempted. The lock is already dropped and memory is freed.
Fix the bug in rev. 1.134. In devfs_allocv_drop_refs(), when not_found == 2
and drop_dm_lock is true, no unlocking shall be attempted. The lock is
already dropped and memory is freed.

Found with:	Coverity Prevent(tm)
CID:	1536
Approved by:	pjd (mentor)

jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase,jrobhoward/SCADAbase