Replace virStoragePoolFree with virObjectUnref

Since virStoragePoolFree will call virObjectUnref anyway, let's just use that
directly so as to avoid the possibility that we inadvertently clear out
a pending error message when using the public API.

daemon/remote.c

@@ -4665,7 +4665,7 @@ remoteDispatchConnectListAllStoragePools(virNetServerPtr server ATTRIBUTE_UNUSED
         virNetMessageSaveError(rerr);
     if (pools && npools > 0) {
         for (i = 0; i < npools; i++)
-            virStoragePoolFree(pools[i]);
+            virObjectUnref(pools[i]);
         VIR_FREE(pools);
     }
     return rv;
@@ -4731,8 +4731,7 @@ remoteDispatchStoragePoolListAllVolumes(virNetServerPtr server ATTRIBUTE_UNUSED,
             virObjectUnref(vols[i]);
         VIR_FREE(vols);
     }
-    if (pool)
-        virStoragePoolFree(pool);
+    virObjectUnref(pool);
     return rv;
 }