host: simtrace2-sniff: init exit code

Early failure i.e. of libusb return random values as exit code.

Change-Id: If920824d35c1f37efe16440b5fb190ca0fb19148

host/src/simtrace2-sniff.c

@@ -328,7 +328,7 @@ static void signal_handler(int signal)
 
 int main(int argc, char **argv)
 {
-	int i, rc, ret;
+	int i, rc, ret = 1;
 	print_welcome();
 
 	/* Parse arguments */