Don't loop mount store if running on XFS natively
Don't loop mount store if running on XFS natively

* Only if store_size_bytes is set to 0

[#147439311]

Signed-off-by: Tiago Scolari <f438736fd7dd1cb07f8d2a37f4499d0a0272a752@pivotal.io>

masters-of-cats/grootfs-release,masters-of-cats/grootfs-release