[Libfix] Remove rpyc_get_connection() dependency from code

Problem:
`g.rpyc_get_connection()` has a limitaion where it can't
convert python2 calls to python3 calls. Due to this a large
number of testcases fail when executed from a python2 machine
on a python3 only setup or visa versa with the below stack trace:
```
E  ========= Remote Traceback (1) =========
E  Traceback (most recent call last):
E  File "/root/tmp.tL8Eqx7d8l/rpyc/core/protocol.py", line 323, in _dispatch_request
E       res = self._HANDLERS[handler](self, *args)
E  File "/root/tmp.tL8Eqx7d8l/rpyc/core/protocol.py", line 591, in _handle_inspect
E       if hasattr(self._local_objects[id_pack], '____conn__'):
E  File "/root/tmp.tL8Eqx7d8l/rpyc/lib/colls.py", line 110, in __getitem__
E       return self._dict[key][0]
E  KeyError: (b'rpyc.core.service.SlaveService', 94282642994712, 140067150858560)
```

Solution:
The solution here is to modify the code to not use
`g.rpyc_get_connection()`. The following changes are done
to accomplish it:
1)Remove code which uses g.rpyc_get_connection() and use generic
logic in functions:
 a. do_bricks_exist_in_shd_volfile()
 b. get_disk_usage()
 c. mount_volume()
 d. list_files()
 f. append_string_to_file()
2)Create files which can be uploaded and executed on
clients/servers to avoid rpc calls in functions:
 a. calculate_hash()
 b. validate_files_in_dir()
3)Modify setup.py to push the below files to
`/usr/share/glustolibs/scripts/`:
 a.compute_hash.py
 b.walk_dir.py

Change-Id: I00a81a88382bf3f8b366753eebdb2999260788ca
Signed-off-by: kshithijiyer <kshithij.ki@gmail.com>

1 files changed, 5 insertions, 18 deletions

diff --git a/glustolibs-gluster/glustolibs/gluster/mount_ops.py b/glustolibs-gluster/glustolibs/gluster/mount_ops.py
index c41ef8528..02dc0a253 100755
--- a/glustolibs-gluster/glustolibs/gluster/mount_ops.py
+++ b/glustolibs-gluster/glustolibs/gluster/mount_ops.py
@@ -1,5 +1,5 @@
 #!/usr/bin/env python
-#  Copyright (C) 2015-2016  Red Hat, Inc. <http://www.redhat.com>
+#  Copyright (C) 2015-2020 Red Hat, Inc. <http://www.redhat.com>
 #
 #  This program is free software; you can redistribute it and/or modify
 #  it under the terms of the GNU General Public License as published by
@@ -356,23 +356,10 @@ def mount_volume(volname, mtype, mpoint, mserver, mclient, options='',
 
         # Check if client is running rhel. If so add specific options
         cifs_options = ""
-        try:
-            conn = g.rpyc_get_connection(mclient, user=user)
-            if conn is None:
-                g.log.error("Unable to get connection to %s on node %s"
-                            " in mount_volume()", user, mclient)
-                return (1, '', '')
-
-            os, version, name = conn.modules.platform.linux_distribution()
-            if "Santiago" in name:
-                cifs_options = "sec=ntlmssp"
-        except Exception as e:
-            g.log.error("Exception occurred while getting the platform "
-                        "of node %s: %s", mclient, str(e))
-            return (1, '', '')
-        finally:
-            g.rpyc_close_connection(host=mclient, user=user)
-
+        cmd = "cat /etc/redhat-release | grep Santiago"
+        ret, _, _ = g.run(mclient, cmd, user=user)
+        if not ret:
+            cifs_options = "sec=ntlmssp"
         mcmd = ("mount -t cifs -o username=%s,password=%s,%s "
                 "\\\\\\\\%s\\\\gluster-%s %s" % (smbuser, smbpasswd,
                                                  cifs_options, mserver,