State Service SetCharm Bug

Add test coverage to a block of code in Service.SetCharm by causing the
the first transaction attempt to fail such that the code gets executed.
Fix a bug in that code block where life was being looked for on the
settings doc instead of the services doc.
Merge branch 'master' of https://github.com/juju/juju into setcharm-bug
Merge pull request #1099 from waigani/setcharm-bug

State Service SetCharm Bug

Add test coverage to a block of code in Service.SetCharm by causing the
the first transaction attempt to fail such that the code gets executed.
Fix a bug in that code block where life was being looked for on the
settings doc instead of the services doc.