Detect description in quilt patches

From: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>

The current logic imports the whole quilt patch as description - the changes
themselves are correctly applied, luckily, but the description must be fixed up
by hand.
So, detect "Index: " lines as patch start. I've heard rumors that also
Subversion generates this format, so we become compatible with it, too.

Signed-off-by: Paolo 'Blaisorblade' Giarrusso <blaisorblade@yahoo.it>