Bug 448101 - support fragments generation.

This is one giant hack and needs total rewrite, but it would be good if
the repo2runnable could write the .info file on the basis of metadata.

Change-Id: Iacb22ccdf9e72a9415bb845f1cf2944f59382f0d
Signed-off-by: Krzysztof Daniel <krzysztof.daniel@gmail.com>
[rgrunber@redhat.com: Use SimpleConfiguratiorManipulatorImpl for
fragment.info. Remove fragment.profile from p2 Droplets format.]
Signed-off-by: Roland Grunberg <rgrunber@redhat.com>