Disable mongo HA set up for local provider

Disable mongo HA set up for local provider

Recent changes to mongo startup to cater for
replicate sets and other HA infrastructure
breaks on the local provider. We don't really
want HA on the local provider anyway. So this
branch disables the HA setup part of mongo
for the local provider. The check used is
consistent with other local provider checks
inside jujud (as wrong as it is) and there 
are no tests specifically for the local
provider case (since the jujud tests just
don't cater for it). But it has been tested
live locally.

https://code.launchpad.net/~wallyworld/juju-core/disable-local-HA/+merge/215797

(do not edit description out of merge proposal)

[wallyworld, 2014-04-15 03:44:47]

Please take a look.

[axw, 2014-04-15 04:05:01]

On 2014/04/15 03:44:47, wallyworld wrote:
> Please take a look.

I really wish we didn't have to do it like this, but LGTM as a bandaid.

[axw, 2014-04-15 04:05:41]

Forgot to mail...

https://codereview.appspot.com/87830044/diff/1/agent/mongo/mongo.go
File agent/mongo/mongo.go (right):

https://codereview.appspot.com/87830044/diff/1/agent/mongo/mongo.go#newcode291
agent/mongo/mongo.go:291: mongoCmd += " --replSet " + replicaSetName
--keyFile is also only relevant to HA