Manage updates to keystone user password with keystone_user

Fix bug 1170380

o Test if the current password works and if not reset it allowing users
  to reset passwords with puppet
o Also move admin token from command line of keystone command in
  favour of using a env variable
o Note : this will break folsom support

Change-Id: I4bae9cad767cdd141ae76343298f7ac43c2a1f90
Merge "Manage updates to keystone user password with keystone_user"