nwfilter: Fix memory leak in virNWFilterIPAddrMapAddIPAddr

If virNWFilterHashTablePut fails, then the @val was leaked.
Signed-off-by: NZhiPeng Lu <lu.zhipeng@zte.com.cn>

src/conf/nwfilter_ipaddrmap.c

@@ -61,6 +61,8 @@ virNWFilterIPAddrMapAddIPAddr(const char *ifname, char *addr)
         if (!val)
             goto cleanup;
         ret = virNWFilterHashTablePut(ipAddressMap, ifname, val);
+        if (ret < 0)
+            virNWFilterVarValueFree(val);
         goto cleanup;
     } else {
         if (virNWFilterVarValueAddValue(val, addr) < 0)