Force apt-get install in case of other prompts.
Merge pull request #929 from edx/jarv/release-fixes

Jarv/release fixes
updating ami for official release
Merge pull request #930 from edx/jarv/release-ami-update

Jarv/release ami update
Merge pull request #931 from edx/jarv/release-ami-update

updating ami for official release
typo
Merge pull request #933 from edx/han/update-script

typo
Add a robots.txt file if robot rules are defined.
Add the robots section if a robots file exists.
creates the migration user, defaults the maintenance user passwords to
null
adding conditional for mongo read_only user
Re-organize templates to reflect default file location.
use xqueue application user for migrations when
COMMON_MYSQL_MIGRATE_PASS is not set
using edxapp_mysql_user_migrate user to run migrations
adding INDEX permission to migrate user
Update logrotation sources.
Cleaning up dollar vars

typo fix

removing unneeded var declaration

changed ${ vars

changed local vars to $, not ${

typo

changed $region var

changes to ${ vars

changes to lb and rb

typo
There were two copies of these tasks. Removing one.
Merge pull request #926 from edx/feanil/nat_monitor_fix

Force apt-get install in case of other prompts.
Merge pull request #936 from edx/feanil/nginx_robots

Feanil/nginx robots