Added OMCI message parsing tests

Change-Id: Ic864446241c3507dcfb389c7e774d0aa79de3b55
diff --git a/common/frameio/frameio.py b/common/frameio/frameio.py
index 0a222ad..4611c14 100644
--- a/common/frameio/frameio.py
+++ b/common/frameio/frameio.py
@@ -53,7 +53,7 @@
     """
     Return a hexadecimal string encoding of input buffer
     """
-    return ' '.join('%02x' % ord(c) for c in buffer)
+    return ''.join('%02x' % ord(c) for c in buffer)
 
 
 class _SelectWakerDescriptor(object):