PATCH (obvious): Fix a comment, and pass stream to cb_data.

PATCH (obvious): Fix a comment, and pass stream to cb_data.

iterate_over_block_arg_vars is a void function, so does
not return 1 or 0.
print_frame_arg_vars tells it prints on STREAM,
so pass STREAM in the cb_data, not gdb_stdout.

gdb/ChangeLog

2018-05-24  Philippe Waroquiers  <philippe.waroquiers@skynet.be>

	* stack.c (iterate_over_block_arg_vars): Fix comment.
	(print_frame_arg_vars): Pass stream in cb_data, not gdb_stdout.