Fix to update docker-py to 1.9.0 version to avoid exec command hangs through docker-py client.
Also remove the links for ovs interfaces from linux during cleanup.
This would enable the containers to be configured again with the peer interfaces on setup

Change-Id: I923c7ebec2ff0724eb59af11a4c21a260a56772c
diff --git a/src/test/utils/CordContainer.py b/src/test/utils/CordContainer.py
index 95cc477..81addcb 100644
--- a/src/test/utils/CordContainer.py
+++ b/src/test/utils/CordContainer.py
@@ -180,7 +180,7 @@
                     ip.link('set', index=guest, state='up')
                 index += 1
 
-    def execute(self, cmd, tty = True, stream = False, shell = True):
+    def execute(self, cmd, tty = True, stream = False, shell = False):
         res = 0
         if type(cmd) == str:
             cmds = (cmd,)