Added printf format checking to logging function.

This also required changing the logging of "" at the
start of each test to appeal the otherwise-friendly
compiler.

test-tool/test_writesame10_unmap_until_end.c

@@ -36,7 +36,7 @@ test_writesame10_unmap_until_end(void)
 	CHECK_FOR_LBPWS10;
 	CHECK_FOR_SBC;
 
-	logging(LOG_VERBOSE, "");
+	logging(LOG_VERBOSE, LOG_BLANK_LINE);
 	logging(LOG_VERBOSE, "Test WRITESAME10 of 1-256 blocks at the end of the LUN by setting number-of-blocks==0");
 	for (i = 1; i <= 256; i++) {
 		unsigned char *buf = malloc(block_size * i);