Bug 1029: Remove dead code: sal-dom-demo

opendaylight/md-sal/sal-dom-demo 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.

If it needs to be revived in the future it can be retrieved
from git.

Change-Id: I77357764b8a779c444ed173e9e8a29a227ba3bf7
Signed-off-by: Ed Warnicke <eaw@cisco.com>