Bug 1029: Remove dead code: samples/clustersession

opendaylight/samples/clustersession/ is dead code that is not being
built and hasn't for some time.  Its complicating keeping
versions up to date and verifying that they are up to date.

Change-Id: I188f00bd07c11649084aafedc8d9a75850bf71e7
Signed-off-by: Ed Warnicke <eaw@cisco.com>
Merge "Bug 1029: Remove dead code: samples/clustersession"