Take the cred from curthread rather than curproc as curproc would need locking but the credential from curthread (usually) never changes.
Take the cred from curthread rather than curproc as curproc would need
locking but the credential from curthread (usually) never changes.

Discussed with:	jhb
MFC after:	2 weeks

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