test_nfs.py: switch to master_3repl

test_nfs.py historically used master_2repl_1client.
Now that master_3client exists, switch to that as it allows removal
of custom install/cleanup steps.

Fixes: https://pagure.io/freeipa/issue/8027
Signed-off-by: François Cami <fcami@redhat.com>
Reviewed-By: Sergey Orlov <sorlov@redhat.com>
Reviewed-By: Rob Crittenden <rcritten@redhat.com>

ipatests/prci_definitions/nightly_f29.yaml

@@ -1243,7 +1243,7 @@ jobs:
         test_suite: test_integration/test_nfs.py::TestNFS
         template: *ci-master-f29
         timeout: 9000
-        topology: *master_2repl_1client
+        topology: *master_3client
 
   fedora-29/mask:
     requires: [fedora-29/build]

ipatests/prci_definitions/nightly_master.yaml

@@ -1255,7 +1255,7 @@ jobs:
         test_suite: test_integration/test_nfs.py::TestNFS
         template: *ci-master-f30
         timeout: 9000
-        topology: *master_2repl_1client
+        topology: *master_3client
 
   fedora-30/mask:
     requires: [fedora-30/build]

ipatests/prci_definitions/nightly_rawhide.yaml

@@ -1255,7 +1255,7 @@ jobs:
         test_suite: test_integration/test_nfs.py::TestNFS
         template: *ci-master-frawhide
         timeout: 9000
-        topology: *master_2repl_1client
+        topology: *master_3client
 
   fedora-rawhide/automember:
     requires: [fedora-rawhide/build]

ipatests/test_integration/test_nfs.py

@@ -21,7 +21,6 @@ import time
 
 from ipatests.test_integration.base import IntegrationTest
 from ipatests.pytest_ipa.integration import tasks
-from ipaplatform.paths import paths
 
 # give some time for units to stabilize
 # otherwise we get transient errors
@@ -31,28 +30,14 @@ WAIT_AFTER_UNINSTALL = WAIT_AFTER_INSTALL
 
 class TestNFS(IntegrationTest):
 
-    num_replicas = 2
-    num_clients = 1
-    topology = 'star'
-
-    @classmethod
-    def install(cls, mh):
-
-        tasks.install_master(cls.master, setup_dns=True)
-        clients = (cls.clients[0], cls.replicas[0], cls.replicas[1])
-        for client in clients:
-            tasks.backup_file(client, paths.RESOLV_CONF)
-            tasks.config_host_resolvconf_with_master_data(
-                cls.master, client
-            )
-            tasks.install_client(cls.master, client)
-            client.run_command(["cat", "/etc/resolv.conf"])
+    num_clients = 3
+    topology = 'line'
 
     def cleanup(self):
 
         nfssrv = self.clients[0]
-        nfsclt = self.replicas[0]
-        automntclt = self.replicas[1]
+        nfsclt = self.clients[1]
+        automntclt = self.clients[2]
 
         nfsclt.run_command(["umount", "-a", "-t", "nfs4"])
         nfsclt.run_command(["systemctl", "stop", "rpc-gssd"])
@@ -77,9 +62,6 @@ class TestNFS(IntegrationTest):
         nfsclt.run_command(["systemctl", "restart", "nfs-utils"])
         nfssrv.run_command(["systemctl", "restart", "nfs-utils"])
 
-        for client in (nfssrv, nfsclt, automntclt):
-            tasks.restore_files(client)
-
     def test_prepare_users(self):
 
         users = {
@@ -141,7 +123,7 @@ class TestNFS(IntegrationTest):
     def test_krb5_nfs_manual_configuration(self):
 
         nfssrv = self.clients[0]
-        nfsclt = self.replicas[0]
+        nfsclt = self.clients[1]
 
         nfsclt.run_command(["systemctl", "restart", "rpc-gssd"])
         time.sleep(WAIT_AFTER_INSTALL)
@@ -169,7 +151,7 @@ class TestNFS(IntegrationTest):
         """
 
         nfssrv = self.clients[0]
-        automntclt = self.replicas[1]
+        automntclt = self.clients[2]
 
         self.master.run_command([
             "ipa", "automountlocation-add", "seattle"