Partial-Bug: #1360727 1. Replaced async to sync during nfs mount 2. Removed write back option during ext4 mount
Partial-Bug: #1360727
1. Replaced async to sync during nfs mount
2. Removed write back option during ext4 mount

Change-Id: I49d487891bbd4afb5a5173889e6c96b3a9451db5

Juniper/contrail-provisioning,Juniper/contrail-provisioning