Allow deletion of files by patches in Format: 3.0 (quilt)

Allow deletion of files by patches in Format: 3.0 (quilt)

* scripts/Dpkg/Source/Patch.pm (add_diff_directory): New option to
be able to generate a diff for a removed file (instead of ignoring
its deletion).
* scripts/Dpkg/Source/Patch.pm (apply): New option "add_options" to
add some options to the default set of options.
* scripts/Dpkg/Source/Package/V3_0/quilt.pm: Pass -E option to
patch when applying patches without quilt. This will remove
patched files which end up being empty.