Remove cleanups from find_frame_funname

Remove cleanups from find_frame_funname

This changes find_frame_funname to return a unique_xmalloc_ptr and
then fixes up the callers.  This removes several cleanups.

ChangeLog
2017-09-11  Tom Tromey  <tom@tromey.com>

	* ada-lang.c (is_known_support_routine): Update.
	(ada_unhandled_exception_name_addr_from_raise): Update.
	* guile/scm-frame.c (gdbscm_frame_name): Update.
	* python/py-frame.c (frapy_name): Update.
	(frapy_function): Update.
	* stack.h (find_frame_funname): Update.
	* stack.c (find_frame_funname): Return unique_xmalloc_ptr.
	(print_frame): Update.