Properly synchronize access to the pmap in pmap_extract_and_hold().
Properly synchronize access to the pmap in pmap_extract_and_hold().

Eliminate an unneeded variable from pmap_extract_and_hold().

Tested by: cognet@

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