- Add gnome-software-add-default-yast-appfolder.patch to add a
YaST app-folder by default, in addition to existing app-folders
Sundry and Utilities; fixes boo#897713.

- Move %lang_package before the definition of
zypp-plugin-appstream to not confuse RPM with the redefined
version of the subpackage.

- Split InstallAppdata.sh in an own package libzypp-plugin-appdata:
other software centers might have to rely on this as well in the
future.
- Add appstream-glib Requires and minimum version for libzypp to
libzypp-plugin-appdata.

- Drop PackageKit-branding-upstream Requires: PK 1.0.0 got a major
rework and dropped the DesktopFile database. So the 'openSUSE'
branded package is good enough.
- Add InstallAppdata.sh: the script is executed by libzypp whenever
some repos are refreshed. The script extracts the appstream data
from the repo metadata and installs it into the 'well known'
location on the file system (/usr/share/app-info).