The desired behavior is to _not_ add the ppa signing key when check_mode is
enabled.  This fix corrects the conditional logic to comply with the stated
behavior.

Signed-off-by: Brian Coca <briancoca+dev@gmail.com>

on Mint as it work on Debian, fix #4587.

PPAs are not supported however, since that's a Ubuntu specific feature
and mint is detected as a generic distribution and use a different
codename than the Ubuntu release it is based on, which mean that apt_repository
cannot add detect and add the proper url without a better heuristic.

Before this fix

  TASK: [apt_repository repo='ppa:vbernat/haproxy-1.5'] *************************
  failed: [134.226.115.202] => {"cmd": ["apt-key", "adv", "--recv-keys", "--keyserver", "keyserver.ubuntu.com", "CFFB779AADC995E4F350A060505D97A41C61B9CD"], "failed": true, "rc": 2}
  stderr: gpg: requesting key 1C61B9CD from hkp server keyserver.ubuntu.com
  gpg: no valid OpenPGP data found.
  gpg: Total number processed: 0

After the fix

  TASK: [apt_repository repo='ppa:vbernat/haproxy-1.5'] *************************
  changed: [134.226.115.202]

Fixes #4311

The default behavior is to update_cache if changed.

If you add more then one repo, you may not want to update cache for every repo separately.
So you can now disable update_cache with this new option e.g. update_cache=no

Updating cache can also be handled using the apt module.

use either pycurl or wget to download from launchpad, also improve error message if neither is installed

use pycurl instead of urllib2 when talking to launchpad to actually get SSL cert verification, see https://bugs.launchpad.net/ubuntu/+source/software-properties/+bug/915210 or CVE-2011-4407 for a previous similar issue in software-properties

1. Debian Squeeze is supported out of box now.
2. Repository type "deb" or "deb-src" should be explicitly specified.
3. If a source had beed added it must be possible to remove it.
4. PPA can be only used against Ubuntu hosts.

  Migrated all examples: in DOCUMENTATION=''' string to standalone EXAMPLES=''' string
  Added deprecation warning to moduledev.rst and remove deprecated example from it
  Fixed up a few typos and uppercased some acronyms.
  add consistency to how EXAMPLES are formatted

This updates the following modules to support check_mode:
* apt_key
* apt_repository
* easy_install
* pip - will always report changed due to the way it handles state
* seboolean
* selinux
* slurp - since nothing changes, it just adds that it supports
  check_mode
* subversion - reports changed when checking out new repo and
  when updating.
* supervisorctl
* svr4pkg

See issue #2114.

This adds two dependencies to the apt_repository module:  apt and
apt_pkg.  These come from the package python-apt.  This is used to parse
the host's sources.list and examine whether the repo is already
configured.  This then eliminates the unnecessary
'add-apt-repository --remove' from running.

This updates apt, apt_repository, command, cron, easy_install, facter,
fireball, git, group, mount, ohai, pip, service, setup, subversion,
supervisorctl, svr4pkg, user, and yum to take advantage of run_command
in module_common.py.