* cli/cli-setshow.c (do_setshow_command): Handle case 'var_filename'

	* cli/cli-setshow.c (do_setshow_command): Handle case 'var_filename'
	and case 'var_optional_filename' together.
	* infcmd.c (_initialize_infcmd): Call add_setshow_string_noescape_cmd
	instead of add_setshow_optional_filename_cmd for setshow command
	'args'.  Set completer for 'set args'.

gdb/testsuite:

	* gdb.base/setshow.exp: Test 'set args ~'.