Fixed pkg_add so when it does not find a package, it returns != 0.
Fixed pkg_add so when it does not find a package, it returns != 0.

PR:		bin/23083
Submitted by:	Patch submitted by Maxime Henrion <mux@qualys.com>
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