This fixes TgtAdm Target Objects not to regenerate random
username/password every time initialize_connection is called,
as TgtAdm doesn't accept the change while the initiator is
connected. This fixes the live-migration of nova instances which
have volumes attached.
Change-Id: I1b48a66da5a0d8726490f50c2ee58352c42d9587
Closes-Bug: #1408162
Related-Bug: #1383509