wait_for_inferior and errors thrown from target_wait

wait_for_inferior and errors thrown from target_wait

Noticed that if an error is thrown out of target_wait, we miss running
finish_thread_state_cleanup.

Tested on x86_64 Fedora 20, with "maint set target-async off".

gdb/ChangeLog:
2015-04-01  Pedro Alves  <palves@redhat.com>

	* infrun.c (wait_for_inferior): Install the
	finish_thread_state_cleanup cleanup across the whole function, not
	just around handle_inferior_event.