New deployer version.

New deployer version.

The new deployer fixes several bugs, including
- unit errors during deployments;
- only watching the units belonging to services included
  in the bundle being deployed;
- fixed a failure in deploying a bundle when a unit is
  already in error in the environment;
- gui bundle imports can use revision-less charm urls.

Also updated the guiserver/deployer interaction to reflect
changes in the deployer.

Tests: `make unittest`.
QA:
- bootstrap a Juju env;
- deploy the charm (`make deploy`);
- wait for the charm to be ready;
- start watching the guiserver logs:
  `juju ssh juju-gui/0 sudo tailf /var/log/upstart/guiserver.log`;
- from the GUI, deploy the bundle in http://pastebin.ubuntu.com/6965041/ :
  it includes a bad-wolf failtester service that will 
  fail with an install error;
- even if bad-wolf units fail, the deployment proceeds: 
  the relation between wordpress and mysql is eventually established 
  and errors are printed to the guiserver logs;
- wait for the first deployment to be completed;
- from the GUI, deploy the bundle in http://pastebin.ubuntu.com/6965647/ :
  it just includes one haproxy service;
- ensure the bundle deployment proceeds correctly even if
  the environments contains units in an error state;
- done, thank you, destroy the juju environment.

https://code.launchpad.net/~frankban/charms/precise/juju-gui/deployer-unit-errors/+merge/207452

(do not edit description out of merge proposal)

[frankban, 2014-02-20 14:45:33]

Please take a look.

[bac, 2014-02-20 19:41:40]

LGTM and QA-ok.  Thanks.

[frankban, 2014-02-21 10:26:56]

*** Submitted:

New deployer version.

The new deployer fixes several bugs, including
- unit errors during deployments;
- only watching the units belonging to services included
  in the bundle being deployed;
- fixed a failure in deploying a bundle when a unit is
  already in error in the environment;
- gui bundle imports can use revision-less charm urls.

Also updated the guiserver/deployer interaction to reflect
changes in the deployer.

Tests: `make unittest`.
QA:
- bootstrap a Juju env;
- deploy the charm (`make deploy`);
- wait for the charm to be ready;
- start watching the guiserver logs:
  `juju ssh juju-gui/0 sudo tailf /var/log/upstart/guiserver.log`;
- from the GUI, deploy the bundle in http://pastebin.ubuntu.com/6965041/ :
  it includes a bad-wolf failtester service that will 
  fail with an install error;
- even if bad-wolf units fail, the deployment proceeds: 
  the relation between wordpress and mysql is eventually established 
  and errors are printed to the guiserver logs;
- wait for the first deployment to be completed;
- from the GUI, deploy the bundle in http://pastebin.ubuntu.com/6965647/ :
  it just includes one haproxy service;
- ensure the bundle deployment proceeds correctly even if
  the environments contains units in an error state;
- done, thank you, destroy the juju environment.

R=bac
CC=
https://codereview.appspot.com/63570048