Code review comment for lp:~deryck/launchpad/enable-tracking-link-perms-512378

This is a fix for bug 512378.

For projects that don't use malone for bug tracking, we changed the bugs
home page (i.e. https://bugs.edge.launchpad.net/malone/) to not display
anything except a message that "[PROJECT] doesn't use Launchpad for bug
tracking." There was also a link to "Enable bug tracking."

Formerly, this link didn't check to see if the user had permissions to
edit the project, so the link showed for everyone, even if they couldn't
change the setting. My branch fixes this and only shows the link to the
appropriate person.

== Tests ==

The home page info test has been updated to now confirm the link is correct.

./bin/test -cvvt xx-front-page-info.txt

== Demo and Q/A ==

To demo on the dev server, create a new project and don't enable bug
tracking. Ensure that you (the owner) can see the link on the project's
bugs home page. Log out and back in again as another user and confirm
this user doesn't see the link.

To QA on edge or staging, visit a project that doesn't use Launchpad for
bug tracking, e.g. https://bugs.edge.launchpad.net/firefox. Confirm
that there is no link to "Enable bug tracking."

= Launchpad lint =

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

Linting changed files:
  lib/lp/bugs/browser/bugtarget.py
  lib/lp/bugs/stories/bugs/xx-front-page-info.txt
  lib/lp/bugs/templates/bugtarget-bugs.pt