gdb/

gdb/
	Tidy up the code.
	* mi/mi-cmd-var.c (mi_cmd_var_update): Remove variable nv.  Move
	variables var, rootlist and cr to their local sub-block.  Move the
	make_cleanup_ui_out_tuple_begin_end, make_cleanup_ui_out_list_begin_end
	and do_cleanups calls to the common base block.  Remove the zero NV
	check.