Fix inverted logic bug

Fix inverted logic bug

During reviews, I changed the success/failure variables from int to bool, but
missed updating the code in a couple spots.  Given the logic inversion, the
gdbserver code fails instead of succeeding.

Fixed with the following patch. Seems fairly obvious, so I'll push it soon.

gdbserver/ChangeLog:

2021-03-30  Luis Machado  <luis.machado@linaro.org>

	* server.cc (handle_general_set, handle_query): Update variable
	to bool and fix verification logic.