Use juju-mongodb on trusty.

Use juju-mongodb on trusty.

This branch does the simplest thing that can work.
For trusty, juju-mongodb is always used, for other
series mongodb-server is used.

This does mean that the local provider on trusty will
now depend on juju-mongodb.  James Page is aware, and
will make the dependency required for the juju-local
package when we tell him.

Tested on the local provider on trusty, and ec2 using
precise.

https://code.launchpad.net/~thumper/juju-core/juju-mongodb/+merge/211642

(do not edit description out of merge proposal)

[thumper, 2014-03-18 22:28:42]

Please take a look.

[wallyworld, 2014-03-18 22:51:07]

LGTM but there's no test for the trusty vs non trusty specific content of cloud
init. I think we need that added.

https://codereview.appspot.com/77300044/diff/1/agent/mongo/mongo.go
File agent/mongo/mongo.go (right):

https://codereview.appspot.com/77300044/diff/1/agent/mongo/mongo.go#newcode75
agent/mongo/mongo.go:75: mongodPath := MongodPathForSeries("some-series")
we have version.readSeries()
Why not use that (after the necessary tweaking to expose the functionality)?

[dave_cheney.net, 2014-03-19 02:58:45]

LGTM with one minor comment

https://codereview.appspot.com/77300044/diff/1/agent/mongo/mongo.go
File agent/mongo/mongo.go (right):

https://codereview.appspot.com/77300044/diff/1/agent/mongo/mongo.go#newcode35
agent/mongo/mongo.go:35: if series == "trusty" {
I don't like the idea that we have to remember to update this in 7 months.

How about

switch series {
case "precise", "raring", "saucy":
    return "mongodb-server"
default:
    // trusty and onwards
    return :juju-mongodb"
}

https://codereview.appspot.com/77300044/diff/1/agent/mongo/mongo.go#newcode47
agent/mongo/mongo.go:47: return MongodbServerPath
same as above