close file before renaming

Renaming an open file is not possible on windows
Adds the 'maas-bridge-interface' option to MAAS configuration
	- By default 'eth0' is used, but this fails on some setups like LP: #1271144 when
	using (p1p2, eth2, ..) interfaces.
- Minor fixes according to @wallyworld observations
- Fixed according to @axw comment.
	- For backward-compatibility, network-bridge is an empty string by default "eth0" will be returned.
remove old fallback code
state/apiserver: Return filename from Backup API

This change adds a Content-Disposition header to backup API responses
which contains the server-generated backup filename. This becomes
important once backups start being stored server side (soon) but also
simplifies the client side of the backup API (no need to generate
backup filenames).
Fix imports.
Merge pull request #264 from howbazaar/remove-old-debug-code

remove old fallback code

No longer needed.
bug fix for lp:1212538
Merge pull request #268 from mattyw/check-machine-before-deploy

fix for lp:1212538: cmd/juju: deploy --to a non existent machine fails too late in the process

https://bugs.launchpad.net/juju-core/+bug/1212538.

There was already a test for the behaviour of deploying to a machine that didn't exist. But it was passing for the wrong reasons.

Currently deploying to a machine that doesn't exists still creates the service in the environment - but it won't be deployed- even when the correct machine id is added.

This fix will prevent a service being deployed if the machine doesn't exist.

Only applies if using the "--to" flag
environmentserver: move connection and authentication info
Fixing comments, removing unused file
environmentserver: moving BootstrapNonce to from environs to agent
Merge pull request #269 from wwitzel3/019-environmentserver

Moving connection and authentication information. (Remove state from environs, Part 1)

This is the first part of a series of branches that will ultimately remove the dependency on state from the environs package.
Reopen mongo sessions between replset initiation attempts

Also, reinstate a change made by mfoord to call
CurrentStatus after attempting intiation, and
refresh session between attempts.

https://bugs.launchpad.net/juju-core/+bug/1339240
Specify a smaller mongo oplog size on local provider

Since the local provider has a single Mongo instance,
the oplog is unuseful. We reduce the size to speed up
preallocation.
Update goamz in dependencies.tsv
Merge pull request #227 from niedbalski/fix_1271144

Add 'network-bridge' option to MAAS configuration

I exposed the variable 'network-bridge'' to allow users to specify to which network interface
the bridge should be bound to.

MAAS provider uses 'eth0' as the default network interface used to build the bridge br0, on some scenarios like LP: #1271144  (p1p2, eth2, ..) this assertion is not true.
Merge pull request #270 from axw/lp1338179-local-oplog

Specify a smaller mongo oplog size on local provider

Since the local provider has a single Mongo instance,
the oplog is unuseful. We reduce the size to speed up
preallocation.

Fixes https://bugs.launchpad.net/juju-core/+bug/1338179
Extend replSetGetStatus timeout, add a test