pin: Fix the template.

In APT preferences files the only allowed comments are lines that start
with `Explanation:`, commented lines that start with a # trigger a
myriad of interesting bugs. This is considered a feature of APT.

Because we're only ever writing a single file at a time with only a #
comment at the top we were getting away with this but it shouldn't be
there in the first place.
pin: caller_module_name is not a topscope variable
unattended-upgrades: Fix origins for Squeeze.

Because Squeeze is now oldstable we need to add an oldstable line too
otherwise security updates won't be picked up. This is still because we
can't match on codename.
Merge pull request #281 from daenney/unattended-upgrades-squeeze-origins

unattended-upgrades: Fix origins for Squeeze.
Merge pull request #280 from daenney/fix-pin-comments

Fix pin comments
Add security warning re: short keys
Merge pull request #282 from laurenrother/security

Add security warning re: short keys
Writing proxy configuration in apt.conf.d/01proxy.

This commit changes the proxy file name to be more consistent with other files
in `apt.conf.d`. The old file (`apt.conf.d/proxy`) is removed.

Tests has been updated.
Merge pull request #283 from johanfleury/master

Change proxy's configuration file to be consistent with other config files in apt.conf.d
Prepare metadata for supported module release.
(cherry picked from commit ab03a989df37df3660f0916519d0f78f7ab73a13)
Add back in missing fields to work around Puppet bug.
(cherry picked from commit dc472717163d30a4463f687a577238ec2539601c)
Merge pull request #285 from blkperl/fix_metadata

Fix metadata.json file
Do not add bogus line to apt preference file on Debian Wheezy
Remove the preference file for all supported platforms when in purge mode
Updated readme to indicate danger of setting preference purge options
Testing if we are not touching the preference file when purge mode is off
Fixed acceptance spec and add debian nodeset
Some code cleaning
Add dpaulus to the contributors list
Merge pull request #290 from dpnl87/wheezy-preference-fix

Do not add bogus line to apt preference file on Debian Wheezy