* bus/config-parser-trivial.c (check_return_values): disable a
	test that hardcoded the bus user's name

	* bus/dispatch.c (bus_dispatch_test_conf): remove the "if
	(!use_launcher)" around the tests, they were only failing because
	we didn't pass through all the expected errors from the helper.

	* bus/activation-exit-codes.h
	(BUS_SPAWN_EXIT_CODE_CHILD_SIGNALED): add a code for child segfaulting
	(BUS_SPAWN_EXIT_CODE_GENERIC_FAILURE): make "1" be a generic
	failure code, so if a third party launch helper were written it
	could just always return 1 on failure.