Use 'void' for zero-argument functions

According to the C standard,
it is desirable to give the type 'void'
to functions have no argument.

Closes #1631

src/config.c

@@ -72,7 +72,7 @@ void appendServerSaveParams(time_t seconds, int changes) {
     server.saveparamslen++;
 }
 
-void resetServerSaveParams() {
+void resetServerSaveParams(void) {
     zfree(server.saveparams);
     server.saveparams = NULL;
     server.saveparamslen = 0;