[binutils-gdb] Constify some commands in symmisc.c

[sergiodj+buildbot@sergiodj.net]

*** TEST RESULTS FOR COMMIT e99c83e741949cb7ae9f4ed449768e8f89ae02bf ***

Author: Tom Tromey <tom@tromey.com>
Branch: master
Commit: e99c83e741949cb7ae9f4ed449768e8f89ae02bf

Constify some commands in symmisc.c

gdb/ChangeLog
2017-09-27  Tom Tromey  <tom@tromey.com>

	* symmisc.c (maintenance_print_symbols)
	(maintenance_print_msymbols, maintenance_print_objfiles)
	(maintenance_info_symtabs, maintenance_check_symtabs)
	(maintenance_expand_symtabs, maintenance_info_line_tables):
	Constify.