vm: ignore RS pin (pre-allocate) requests for now

. done by RS to reduce/remove dependency on VM for recovery
	. RS has the default stack size of 64MB since the nosegments
	  change, using a huge amount of unused memory to pre-allocate
	. ignore these requests until actually required (i.e. being able
	  to survive VM crashes)

Thanks to pikpik for investigating why RS was so huge.

servers/vm/rs.c

@@ -180,8 +180,20 @@ int do_rs_memctl(message *m_ptr)
 	switch(req)
 	{
 	case VM_RS_MEM_PIN:
+
+		/* Do not perform VM_RS_MEM_PIN yet - it costs the full
+		 * size of the RS stack (64MB by default) in memory,
+		 * and it's needed for functionality that isn't complete /
+		 * merged in current Minix (surviving VM crashes).
+		 */
+
+#if 0
 		r = map_pin_memory(vmp);
 		return r;
+#else
+		return OK;
+#endif
+
 	case VM_RS_MEM_MAKE_VM:
 		r = rs_memctl_make_vm_instance(vmp);
 		return r;