Code review comment for lp:~adeuring/launchpad/bug-494075

When psycopg QueryCancelError occurs, we see only the SQL statement leading to the timeout and its parameters, but not the details of the QueryCancelError. This makes it hard to understand what heppend for example in OOPS-1438B2246.

This branch adds the original QueryCancelError message to the data reported for TimeoutErrors.

test: ./bin/test -vv -t test_adapter.txt

= Launchpad lint =

Checking for conflicts. and issues in doctests and templates.
Running jslint, xmllint, pyflakes, and pylint.
Using normal rules.

Linting changed files:
  lib/canonical/launchpad/webapp/adapter.py
  lib/canonical/launchpad/webapp/ftests/test_adapter.txt
abel@klato4:~/canonical/lp-branches/bug-494075$ make lint
= Launchpad lint =

Checking for conflicts. and issues in doctests and templates.
Running jslint, xmllint, pyflakes, and pylint.
Using normal rules.

Linting changed files:
  lib/canonical/launchpad/webapp/adapter.py
  lib/canonical/launchpad/webapp/ftests/test_adapter.txt