Don't run voltha processes if already running just to avoid multiple running instances.
Change default voltha interface in manifest-voltha to eth0.

Change-Id: I28c19d8c9836e9f5809e1ea12bfcd57b2a596ddc
diff --git a/src/test/utils/CordTestUtils.py b/src/test/utils/CordTestUtils.py
index 6d46c16..f21c4e9 100644
--- a/src/test/utils/CordTestUtils.py
+++ b/src/test/utils/CordTestUtils.py
@@ -12,7 +12,7 @@
 
 # we use subprocess as commands.getstatusoutput would be deprecated
 def getstatusoutput(cmd):
-    command = [ '/bin/sh', '-c', cmd ]
+    command = [ '/bin/bash', '-c', cmd ]
     p = subprocess.Popen(command, stdout = subprocess.PIPE)
     out, _ = p.communicate()
     return p.returncode, out.strip()