GENIUS-202 GENIUS-257 Retry for Unlock() & IdManager calls tryLock()

GENIUS-202 GENIUS-257 Retry for Unlock() & IdManager calls tryLock()

** LockManager's unlock() method now retries 10 times in case of
exception is thrown. The interval between retries is 1 sec.

** LockManager's lock() method now eternally retries in case of
DataStoreUnavailableException and OptimisticLockFailedException
otherwise it returns FailedRpcResult.

** IdManager no longer calls LockManager's lock() api. It now calls
LockManager's tryLock() api which internally retries for 10 times.
Idmanager returns failure if lock is not acquired after specified lock
attempts. After this change, it is the responsibility of the consumers of
Idmanager to handle these failures.

Change-Id: Ic230e2e4edce4f95ee461ef22ff895368af9663d
Signed-off-by: Ankit Jain <ankit.j.jain@ericsson.com>
Signed-off-by: Amitesh Soni <amitesh.soni@ericsson.com>