getnewvnode() can be called with NULL mp.
getnewvnode() can be called with NULL mp.

Found by:	Coverity Prevent (tm)
Coverity ID:	1521
Confirmed by:	phk

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