Protect nfsm_srvpathsiz() call with the nfsd_mtx lock.
Protect nfsm_srvpathsiz() call with the nfsd_mtx lock.

Reviewed by:	mohans

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