Use docker exec_start api with raw socket = True to avoid hangs while executing a command waiting for result.
Also remove the requirement for a specific docker-py version.

Change-Id: Ia89a425724327db0532d4e6168ed4ed924c4969e
diff --git a/src/test/setup/requirements.txt b/src/test/setup/requirements.txt
index 490bd61..514cc17 100644
--- a/src/test/setup/requirements.txt
+++ b/src/test/setup/requirements.txt
@@ -2,7 +2,7 @@
 scapy==2.3.2
 monotonic
 configObj
-docker-py==1.9.0
+docker-py
 pyyaml
 nsenter
 pyroute2