Fix the number of lwlocks needed by the "fast path" lock patch. It needs

one lock per backend or auxiliary process - the need for a lock for each
aux processes was not accounted for in NumLWLocks(). No-one noticed,
because the three locks needed for the three aux processes fit into the
few extra lwlocks we allocate for 3rd party modules that don't call
RequestAddinLWLocks() (NUM_USER_DEFINED_LWLOCKS, 4 by default).

src/backend/storage/lmgr/lwlock.c

@@ -167,8 +167,8 @@ NumLWLocks(void)
 	/* bufmgr.c needs two for each shared buffer */
 	numLocks += 2 * NBuffers;
 
-	/* lock.c needs one per backend */
-	numLocks += MaxBackends;
+	/* proc.c needs one for each backend or auxiliary process */
+	numLocks += MaxBackends + NUM_AUXILIARY_PROCS;
 
 	/* clog.c needs one per CLOG buffer */
 	numLocks += NUM_CLOG_BUFFERS;