Sort package list for centos_spec
Add CreatePartitionIfNoEphemeralDisk agent setting

* OpenStack stemcells turn this on so flavors without ephemeral disk get
  a partition to use.

Signed-off-by: Adam Stegman <astegman@pivotallabs.com>
Install parted

Agent will use parted when creating a partition for CreatePartitionIfNoEphemeralDisk