change to chmod as privileged user.
Merge pull request #722 from edx/e0d/idempotent-chmod

change to chmod as privileged user.
Merge pull request #741 from edx/e0d/commoncluster

E0d/commoncluster
bug fixes relate to re-location to /edx
Add a new arg just for git refs.

This seperates the git refs from the rest of the vars because the git refs should end up in
the ami document in mongo but the other vars should not.
Add an env tag to studio and edxapp dns names.
Allow studio access for urls with env prefixes.
Run migrations before syncing the DB.
Begin referencing environment and deployment instead of env_type and env_name.
Have only one YAML message header.
Merge pull request #745 from edx/feanil/proper_extra_vars

Feanil/proper extra vars
Updating alternatives.
Merge pull request #746 from edx/e0d/java-alternatives

Updating alternatives.
Merge pull request #743 from edx/e0d/es-bugfixes

bug fixes relate to re-location to /edx
Installing the bigdesk monitoring plugin.
updating to use stat module.
Merge pull request #747 from edx/e0d/es-bigdesk-plugin

Installing the bigdesk monitoring plugin.
Changes to update dhclient search domain.
Merge pull request #748 from edx/e0d/common-dhclient

Changes to update dhclient search domain.
wip