Replace bare excepts with something more responsible

In many cases, this is 'except Exception', but where a more specifc
exception was obvious, that is used instead.
have pylint check for bare except's

Fixes #2540.
fix minor errors
pep8 spacing on files that haven't been touched in a while
Don't log the password in the DB URL

Passwords in logs make security teams twitchy.  Fixes #2896.
Merge pull request #1227 from djmitche/bug2540

Replace bare excepts

Fixes ticket:2540
Merge pull request #1228 from djmitche/bug2896

Don't log the password in the DB URL

Fixes ticket:2896
Re-add syntax error in tutorial (thanks to Marco Paolini)
re-structure cfg-buildslaves manual page

* put documentation for supported latent buildslaves into separate
  documents
* polish a bit each page to give an overview of what they provide

Fixes ticket:2861
Merge sa2ajj/buildbot:bugfix-2861 (PR #1232)