Call wrap_hint in one more spot in py-framefilter.c

PR python/16486 notes that "bt" output is still wrapped differently
when a frame filter is in use.  This patch brings it a bit closer by
adding one more wrap_hint call, in a place where stack.c does this as
well.

gdb/ChangeLog
2018-03-26  Tom Tromey  <tom@tromey.com>

	PR python/16486:
	* python/py-framefilter.c (py_print_args): Call wrap_hint.