If we failed to allocate the file discriptor for the write end of the pipe, then we were corrupting the pipe_zone free list by calling pipeclose on rpipe twice. NULL out rpipe to avoid this.
If we failed to allocate the file discriptor for the write end of
the pipe, then we were corrupting the pipe_zone free list by calling
pipeclose on rpipe twice. NULL out rpipe to avoid this.

Reviewed by:	dillon
Reviewed by:	iedowse

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