Bug fixes for createCell

- Fix for single node cell
- Use onos home instead of environment variable

Change-Id: I20d8bed99ef33a8cf19ba0f587dac7cd30ce09fe
diff --git a/TestON/drivers/common/cli/onosdriver.py b/TestON/drivers/common/cli/onosdriver.py
index 95334fa..8e9b3e0 100644
--- a/TestON/drivers/common/cli/onosdriver.py
+++ b/TestON/drivers/common/cli/onosdriver.py
@@ -18,6 +18,7 @@
 """
 import sys
 import time
+import types
 import pexpect
 import os
 import os.path
@@ -668,12 +669,14 @@
             ~/<self.home>/tools/test/cells/
         """
         # Variable initialization
-        cellDirectory = os.environ["ONOS_ROOT"] + "/tools/test/cells/"
+        cellDirectory = self.home + "/tools/test/cells/"
         # We want to create the cell file in the dependencies directory
         # of TestON first, then copy over to ONOS bench
         tempDirectory = "/tmp/"
         # Create the cell file in the directory for writing ( w+ )
         cellFile = open( tempDirectory + fileName, 'w+' )
+        if isinstance( onosIpAddrs, types.StringType ):
+            onosIpAddrs = [ onosIpAddrs ]
 
         # App string is hardcoded environment variables
         # That you may wish to use by default on startup.