Fix (potential) problematic use cases of qboolean.

xatrix had only one potential problematic use case, putting an int into
qboolean. It would have worked if qboolean is a bool, but better do it
right. No functional change intended.

src/g_svcmds.c

@@ -158,11 +158,11 @@ SV_FilterPacket(char *from)
 	{
 		if ((in & ipfilters[i].mask) == ipfilters[i].compare)
 		{
-			return (int)filterban->value;
+			return (filterban->value != 0);
 		}
 	}
 
-	return (int)!filterban->value;
+	return (filterban->value == 0);
 }
 
 void