package/gnuchess: bump version to 6.2.1

Removed unneeded patches, Debian did the same:
http://metadata.ftp-master.debian.org/changelogs/main/g/gnuchess/unstable_changelog



gnuchess (6.0.2-1) unstable; urgency=low

  * New upstream version (Closes: #637722)
[...]
    - Drop patches

The patch is no longer needed because the gnuchess code has been
reworked. The input.c file no longer exists, and there is no longer a
getline() function being defined.

[Thomas: tweak commit log.]

Signed-off-by: Bernd Kuhls <bernd.kuhls@t-online.de>
Signed-off-by: Thomas Petazzoni <thomas.petazzoni@free-electrons.com>