Bug 1036 - Allow using container in case stmt to preserve uniqueness.

Modify yang-jmx-generator and config-netconf-connector to allow adding
dummy container node.
This allows declaring multiple config modules with same attributes within
single yang module.

Change-Id: I49ae30143e45f590f4be6b4713e048bdf9e72edb
Signed-off-by: Tomas Olvecky <tolvecky@cisco.com>