Fix grab_versions() for cmp nodes

OpenSSH servers are configured during salt minions bootstrap.
But for OpenStack compute nodes, the state openssh is running
one more time with 'state.apply', and disable password authentication.

This breaks grab_versions() fixture which cannot access cmp nodes
to get logs.

- Run 'tar' on minions using salt from cfg nodes instead of
  direct SSH connection

Change-Id: I6de0e42b390c954a981ab060d8503989375b0ebc
diff --git a/tcp_tests/managers/underlay_ssh_manager.py b/tcp_tests/managers/underlay_ssh_manager.py
index 3f5d712..2008fba 100644
--- a/tcp_tests/managers/underlay_ssh_manager.py
+++ b/tcp_tests/managers/underlay_ssh_manager.py
@@ -421,23 +421,22 @@
                        t='{0}_log.tar.gz'.format(artifact_name), d='/var/log'))
         minion_nodes = [ssh for ssh in self.config_ssh
                         if node_role not in ssh['roles']]
-        for node in minion_nodes:
-            LOG.info("Archiving logs on the node {0}"
-                     .format(node['node_name']))
-            try:
-                with self.remote(host=node['host']) as r_node:
-                    r_node.check_call((
-                        'tar '
-                        '--absolute-names '
-                        '--warning=no-file-changed '
-                        '-czf {t} {d}'.format(
-                            t='{0}.tar.gz'.format(node['node_name']),
-                            d='/var/log')),
-                            raise_on_err=False)
-            except Exception:
-                LOG.info("Can not ssh for node {}".format(node))
+
         with self.remote(master_node['node_name']) as r:
             for node in minion_nodes:
+                LOG.info("Archiving logs on the node {0}"
+                         .format(node['node_name']))
+                r.check_call((
+                    "salt '{n}*' cmd.run "
+                    "'tar "
+                    "--absolute-names "
+                    "--warning=no-file-changed "
+                    "-czf {t} {d}'".format(
+                        n=node['node_name'],
+                        t='{0}.tar.gz'.format(node['node_name']),
+                        d='/var/log')),
+                        raise_on_err=False)
+
                 LOG.info("Copying logs from {0} to {1}"
                          .format(node['node_name'], master_node['node_name']))
                 packages_minion_cmd = ("salt '{0}*' cmd.run "