Merge lp://staging/~stub/charms/precise/postgresql/bug-1281600-log_temp_files into lp://staging/charms/postgresql

Looks good to me! Clean addition of a charm parameter, it does what is written on the tin.

+1 LGTM

> +1 LGTM

Upon further review, there are quite a few more changes being included in this MP from the prerequisite branch. There was a merged MP on that branch from around the time this MP was submitted, and the subsequent changes to the prerequisite branch don't necessarily seem related to this change. Those changes (changing and resyncing the charm-helpers branch) seem fine, but the ambiguity makes me less sure about recommending this MP.

Additionally, I wasn't able to get the tests passing, even after doing `make testdeps`. This doesn't seem related to this change, so I'm not certain it should block this MP, but it definitely should be addressed.

Ideally, I would recommend removing the prerequisite branch and including any applicable changes explicitly in this MP. Switching my review to "Needs Information" for clarification and / or removing the prerequisite branch. If you can get `make test` working on a fresh env, as well, that would be even better.

@johnsca

I'm using pipelines and dependant branches to keep the merge proposals to managable size. I'm more than happy to handle landing once the merge proposal and all its dependencies have been approved. In case you would rather review everything as one big diff, I've created https://code.launchpad.net/~stub/charms/precise/postgresql/integration/+merge/233666 .

The tests should run, and do run here with lxc. Important points:
- The default juju environment needs to be bootstrapped
- Bad host keys need to be cleaned out of ~/.ssh/known_hosts and ~root/.ssh/known_hosts (per the outstanding juju bugs)
- Strict host key checking needs to be enabled (or SSH implicitly disables port forwarding, which the tests need).

Unexpected changes come from:

 - Another charmhelpers update I neglected to land earlier ( http://pastebin.ubuntu.com/8287937/ )
 - Some dead code removal removal ( http://pastebin.ubuntu.com/8287920/ )