[binutils-gdb] Remove cleanups from mdebugread.c

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 633cf2548bcd3dafe297e21a1dd3574240280d48 ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: 633cf2548bcd3dafe297e21a1dd3574240280d48

Remove cleanups from mdebugread.c

This removes the remaining cleanups from mdebugread.c, replacing them
with gdb::def_vector.

Tested by the buildbot, though I doubt this exercises mdebugread.

gdb/ChangeLog
2018-05-11  Tom Tromey  <tom@tromey.com>

	* mdebugread.c (parse_partial_symbols, psymtab_to_symtab_1): Use
	gdb::def_vector.