[binutils-gdb] Use gdb_file_up in fbsd-nat.c

[sergiodj+buildbot at sergiodj dot net]

*** TEST RESULTS FOR COMMIT 7cd06d6e89c9c17d358d8edf0b7faa9dd87edc3e ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: 7cd06d6e89c9c17d358d8edf0b7faa9dd87edc3e

Use gdb_file_up in fbsd-nat.c

This updates fbsd-nat.c to use gdb_file_up.  This removes a use of a
cleanup, and helps remove make_cleanup_fclose in a later patch.

I have no way to test this patch.

ChangeLog
2017-08-03  Tom Tromey  <tom@tromey.com>

	* fbsd-nat.c (fbsd_find_memory_regions): Update.