[MERGE] stable-2.13 to stable 2.14

['Brian Foley' via ganeti-devel]

commit 83821549528e1c601d71bcf779809016531d0f7d
Merge: 712ea2f 0df7c24
Author: Brian Foley <bpfo...@google.com>
Date:   Mon Aug 22 11:40:10 2016 +0100

    Merge branch 'stable-2.13' into stable-2.14
    
    * stable-2.13
      Bugfix: migrate needs HypervisorClass, not an instance
    
    Signed-off-by: Brian Foley <bpfo...@google.com>