The Cinder backup manager now uses initiator connectors for
creating and restoring backups for all volume backends, so
this patch adds a connector for GPFS volumes to fix the
backup-create & backup-restore for the GPFS driver.
DocImpact
Change-Id: I49cc52d6df5d0c1b470ced531075d851aa30208d
Implements: blueprint os-brick-gpfs-protocol-support