[binutils-gdb] Use gdb::def_vector in func_command

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT 0b868b60c97b13566cefc8c8f1984225b0165eec ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: 0b868b60c97b13566cefc8c8f1984225b0165eec

Use gdb::def_vector in func_command

This changes func_command to use gdb::def_vector, removing a cleanup.

ChangeLog
2017-09-09  Tom Tromey  <tom@tromey.com>

	* stack.c (func_command): Use gdb::def_vector.