test: fix build warnings for most tests

Let rsync.c continue to warn, it's not complete ...

Signed-off-by: Joachim Wiberg <troglobit@gmail.com>

test/yorn.c

@@ -4,7 +4,7 @@
 
 #include "check.h"
 
-int main(int argc, char *argv[])
+int main(void)
 {
 	int chan[2];
 	int status;