Several changes, with overall effect of simplified writing of
the chroot's sources.list.
* do nothing unless this chroot is marked with launchpad.series
* if apt.enable is not 'false', then always write sources.list
* Drop old code supporting precise.
* Base components and suites on the alias used. If no alias is
used, then the default component or suite is used.
* document the configuration values.
LP: #1872163
(cherry picked from commit 066b078588fe9f6c82518d8bbd1d1b550bbc1eb0)
New changelog entries:
* Don't enforce .tar.bz2 suffix for the tarball, just use what Launchpad
gives us; tar will handle it just fine.
* debian/control: Add Vcs-* fields and push the code to LP.
New changelog entries:
* Fix updating chroots which crashed because there is no series parameter
passed to sbuild-launchpad-chroot in that case. Fortunately we already get
series from config/Launchpad.