Revert "Patch to fix test_rebuild_volume_backed_server"

This reverts commit f0fd5a98d65526f823bf176377ee2059a22142bb.

Reason for revert: merged by mistake

Related-prod: PRODX-43715
Change-Id: I1f1f7ba05f9805db5b91b185ba2f961e109c9299
diff --git a/tempest/api/compute/servers/test_server_actions.py b/tempest/api/compute/servers/test_server_actions.py
index 301db05..21ed0cd 100644
--- a/tempest/api/compute/servers/test_server_actions.py
+++ b/tempest/api/compute/servers/test_server_actions.py
@@ -854,7 +854,7 @@
         # 4.Plain username/password auth, if a password was given.
         linux_client = remote_client.RemoteClient(
             self.get_server_ip(server, self.validation_resources),
-            self.ssh_alt_user,
+            self.ssh_user,
             password=None,
             pkey=self.validation_resources['keypair']['private_key'],
             server=server,
diff --git a/tempest/config.py b/tempest/config.py
index aeef88e..38e2a46 100644
--- a/tempest/config.py
+++ b/tempest/config.py
@@ -907,7 +907,7 @@
                default="root",
                help="User name used to authenticate to an instance."),
     cfg.StrOpt('image_alt_ssh_user',
-               default="cirros",
+               default="root",
                help="User name used to authenticate to an alt instance."),
     cfg.StrOpt('image_ssh_password',
                default="password",