[binutils-gdb] Remove cleanup from ada_collect_symbol_completion_matches

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 790217f6736cc0f0a177a681ba1c7cc5f995cfe7 ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: 790217f6736cc0f0a177a681ba1c7cc5f995cfe7

Remove cleanup from ada_collect_symbol_completion_matches

ada_collect_symbol_completion_matches installs a null_cleanup but not
any other cleanups.  This patch removes it.

ChangeLog
2018-05-21  Tom Tromey  <tom@tromey.com>

	* ada-lang.c (ada_collect_symbol_completion_matches): Remove
	cleanup.