[binutils-gdb] Remove an unlink cleanup

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT b80cf838447322778f04059a1f58b78ffbbeb597 ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: b80cf838447322778f04059a1f58b78ffbbeb597

Remove an unlink cleanup

compile/compile.c had its own cleanup to unlink a file.  This patch
replaces this cleanup with gdb::unlinker.

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

	* compile/compile.c (cleanup_unlink_file): Remove.
	(compile_to_object): Use gdb::unlinker.
	(eval_compile_command): Likewise.