[spec] Easier rebuilding

Signed-off-by: Juha Kallioinen <juha.kallioinen@jolla.com>
[zypp] Supports systemCheck.d directory

Reads files from under /etc/zypp/systemCheck.d (default) and adds the
listed requires and conflicts rules to the system requirements.

Files are read in alphabetical order.

This list of requires/conflicts is updated only when packagekitd is
reloaded.

Signed-off-by: Juha Kallioinen <juha.kallioinen@jolla.com>
Merge pull request #1 from mer-packages/systemcheckd

Support for /etc/zypp/systemCheck.d/ config directory