Enabling Flake8 and import sorting

Enabling flake8 verifications in tox.ini and adding import sorting.
All the plugins have been fixed for flake8 errors and the imports
have been sorted.

Change-Id: Icdefe9a877e891a683cc833315e4c3f94fffbab9
Signed-off-by: sousaedu <eduardo.sousa@canonical.com>
diff --git a/RO-plugin/osm_ro_plugin/vimconn.py b/RO-plugin/osm_ro_plugin/vimconn.py
index cc087f0..b4e936c 100644
--- a/RO-plugin/osm_ro_plugin/vimconn.py
+++ b/RO-plugin/osm_ro_plugin/vimconn.py
@@ -26,17 +26,18 @@
  with the definition of the method to be implemented.
 """
 
-import logging
-import paramiko
-import socket
-from io import StringIO
-import yaml
-import sys
 from email.mime.multipart import MIMEMultipart
 from email.mime.text import MIMEText
 from http import HTTPStatus
+from io import StringIO
+import logging
+import socket
+import sys
 import warnings
 
+import paramiko
+import yaml
+
 __author__ = "Alfonso Tierno, Igor D.C."
 __date__ = "$14-aug-2017 23:59:59$"