Use range-based for loop in remote_add_target_side_condition

Use range-based for loop in remote_add_target_side_condition

Using a range based for loop makes this code a bit more clean and
readable.

The comment above is clearly erroneous, so I've updated it.

gdb/ChangeLog:

	* remote.c (remote_add_target_side_condition): Use range-based
	for loop.  Update comment.