gnu-netcat: Removal of package

gnu-netcat: Removal of package

- gnu-netcat was last updated in 2004 and is not used as a dependency for any IPFire
   addon.
- IPFire has ncat which is used as a dependency for ipfire-netboot, libshout, libvirt
   and squid. gnu-netcat not being required for libvcirt was confirmed by Jonatan.
- nmap/ncat is being actively updated.
- Based on the above this patch is removing gnu-netcat from IPFire.

Signed-off-by: Adolf Belka <adolf.belka@ipfire.org>