Fix AttributeError: replace add_back_node with re_add_node in disk/multi-node failover tests

ClusterRestAPI exposes re_add_node, not add_back_node; the old method only exists on the legacy RestConnection client.

Change-Id: Ief96a5a6ad776f5191f69d4202843248958da194
Reviewed-on: https://review.couchbase.org/c/TAF/+/245756
Reviewed-by: Ashwin <ashwin.govindarajulu@couchbase.com>
Tested-by: Ashwin <ashwin.govindarajulu@couchbase.com>

Author: shivanand-adky

pytests/failover/DiskFailoverTests.py

@@ -309,7 +309,7 @@ def test_disk_autofailover_and_addback_of_node(self):
         self.log.info(self.server_to_fail[0])
         self.nodes = self.cluster_util.get_otp_nodes(self.orchestrator)
         self.log.info("Adding back node {0}".format(self.server_to_fail[0].ip))
-        self.rest.add_back_node("ns_1@{}".format(self.server_to_fail[0].ip))
+        self.rest.re_add_node("ns_1@{}".format(self.server_to_fail[0].ip))
         self.rest.set_recovery_type("ns_1@{}".format(self.server_to_fail[
                                                          0].ip),
                                     self.recovery_strategy)

pytests/failover/MultiNodeAutoFailoverTests.py

@@ -230,7 +230,7 @@ def test_autofailover_and_addback_of_node(self):
         self.sleep(30)
         self.nodes = self.cluster_util.get_nodes(self.orchestrator)
         for node in self.server_to_fail:
-            self.rest.add_back_node("ns_1@{}".format(node.ip))
+            self.rest.re_add_node("ns_1@{}".format(node.ip))
             self.rest.set_recovery_type("ns_1@{}".format(node.ip),
                                         self.recovery_strategy)
         self.rest.rebalance(known_nodes=[node.id for node in self.nodes])