closes #136 - flush network_interfaces handlers before more roles
closes #136 - flush network_interfaces handlers before more roles

this commit should improve scenarios where roles applied after
network_interfaces depend on all the interfaces being configured:
 - network_interfaces configures ib0 for the first time and ib0 did not
   get configured properly during provisioning
 - nfs_mount tries to mount an NFS share on ib0
 - long wait

mantti/fgci-tut,mantti/fgci-tut,mantti/fgci-tut