Replace getCapabilities() with getCapabilities(void)

The latter means no args, the former means any args.

server/modules/routing/debugcli/debugcli.c

@@ -333,7 +333,7 @@ diagnostics(ROUTER *instance, DCB *dcb)
     return; /* Nothing to do currently */
 }
 
-static uint64_t getCapabilities()
+static uint64_t getCapabilities(void)
 {
     return 0;
 }