Don't store the inferior's exit code for --return-child-result in a print routine.

Don't store the inferior's exit code for --return-child-result in a print routine.

A small cleanup - so we can call the print routine without affecting
--return-child-result.

gdb/
2014-05-22  Pedro Alves  <palves@redhat.com>

	* infrun.c (handle_inferior_event): Store the exit code for
	--return-child-result here, instead of ...
	(print_exited_reason): ... here.