libpcap: fix library packaging issues

libpcap: fix library packaging issues

Workaround a bug in patches/100-debian_shared_lib.patch - it attemptss to
extract the library major version from debian/changelog which does not exist
in the vanilla upstream tarball.

Create a fake changelog file for now to satisfy the version extraction
routine until we get around to properly augment the patch.

Fixes: FS#2970
Fixes: 96ee7c8bfd ("libpcap: Update shared-lib patch from Debian to fix linking problems")
Signed-off-by: Jo-Philipp Wich <jo@mein.io>