Add patch to customize okular bugurl

* patches/okular/0001-Hack-in-some-aboutdata-for-GnuPG-Edition.patch:
  Add a quick hack.
* Makefile.am (EXTRA_DIST): Update accordingly.

This is not a proper solution to customize Okular just something
to do this before the release so that we have at least the
bug reporting URL changed etc.

• GnuPG-Bug-Id: T6591