Remove unsafe use of asynchronous I/O (the SIGIO handler could cause

Remove unsafe use of asynchronous I/O (the SIGIO handler could cause
incorrect reentrant calls to the libc memory manager).

Add missing error handling:
  * for an incoming response with an incorrect tid;
  * for a failure to register the response RPC program,

Fix error handling for failure to malloc job descriptor (this needs to
be done before the transient RPC program is registered).

PR:		bin/102143
MFC after:	2 weeks