Switch to using the vpc_class_b for these subnets

I suspect the third change is wrong - as is, it creates a route table,
but I cannot connect to the RDS.  However, there is no local gateway in
10.253.0.0 in loadtest, so the default isn't quite right either.

We should possible make SUBNET_[12]_CIDR easier to override, since I
ended up changing them anyway to use something other than .50.

E0d/service dbs

fix broken test

Provide separate internal/public API endpoints.

update github_post_status.py for jenkins_worker role

This allows us to route LMS requests over an internal ELB while public
JS direct requests to the API go over a separate ELB.

Ubuntu 12.04 doesn't support 'git clone -b'

This is to deal with the issue pointed out in #2036

Feanil/doc store updates

Update the source list after adding git ppa TE-907

App monitoring is triggered on the _APP variable

Tag the paver static assets task

add defaults for interacting with authenticated jenkins API

Move Shibboleth deps to edxapp_common so they'll be available on Jenkins

This lets you run ansible-playbook with --skip-tags gather_static_assets
so you can redeploy edx-platform on your sandbox to test configuration
changes without waiting for paver.

COMMON_ENABLE_NEWRELIC turns on server monitoring and is on for all
sandboxes.  App monitoring should not be enabled for all sandboxes and
since edxapp workers is on all sandboxes, surprise newrelic!

Revert all the docstore related changes.

This allows us to override the read preferences per module store in the lms.

They are not ready to go out yet so revert them until the corresponding edx-platform changes are in.

Indicate that secret key should be changed

Allow us to configure the replicaset name per modulestore.

We need a default docstore config defined even when we override it.

Separate the read preference per docstore.

This way you can change read preference for one of the module stores
without effecting the other.

Also fix whitespace.

Pull out docstore config and move modulestore config.

We need to have different read preferences in the CMS and LMS for modulestore configs so that the lms can read from the nearest node.

Add publicly-accessible ecommerce URL root