Never allow cancelling a transaction twice
trivial: Use updates-testing for Fedora 21
Trivial: do not list systemd-updates in the configure overview.

The functionality to enable/disable it was removed with commit
c660453d3565abee85aa5efd7c18c16b7c794640
Offline-updates: don't allow to disable

Make packagekit-offline-update a static service.
Users believe by disabling the service, the feature would be disabled,
when in fact systemd still brings the user to the system-update.target
but then doesn't perform any action, most of all not removing the
/system-update link, thus ending in a loop.

Link the new static service into system-update.target.wanted, to ensure
system-update.target triggers offline-update.

https://bugzilla.redhat.com/show_bug.cgi?id=988235
Merge pull request #13 from DimStar77/master

Trivial: do not list systemd-updates in the configure overview.
Remove last occurence of box backend from matrix
alpm: Environment initialization refactoring

    - Move pk_alpm_configure_environment to it's own file.
    - Replaced the old safeguard by one using g_once_init_enter.
Don't assume systemd is found if --with-systemdsystemunitdir is passed
zypp: be more specific with the progress status messages
zypp: fix compiler warning (label not used)
zypp: ensure to reach 100% on complete cache_refresh
zypp: fix white-space usage
build: overwrite an existing link for packagekit-offline-update.service

This fixes errors when attempting to locally perform make install more
than once.
Fix configure error introduced by 8eb4725
urpmi: Fix typo in the filter code
Do not install the python helpers unless required
trivial: Update the example spec file
hif: Invalidate offline updates when the rpmdb changes
trivial: Drop unused return value from pk_backend_repo_list_changed
trivial: Don't return a value from void function

Now that pk_backend_repo_list_changed returns void, use g_return_if_fail
instead of g_return_val_if_fail. Thanks to lantw44 for catching this!

Fixes #18.