MFC r200667: Return earlier from linux_do_tkill() when supplied signal number is 0.
MFC r200667:
Return earlier from linux_do_tkill() when supplied signal number is 0.

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