This update for xvfb-run fixes the following issues:

- let Xvfb no longer ignore authority file.
- fix syntax to parse --error-file and --auth-file (bsc#1261252).
- Use `%patch -P N` instead of deprecated `%patchN`.
- actually gzip manpage to match the filename extension.
- Add missing runtime dependencies to which and xauth (bsc#1178672).
- Fixed broken URL for manpage.