[OE-core] Gnupg recipe fixes

[Paul Barker]

I'm setting up a signed apt repository of .deb packages built using OpenEmbedded
and I've ran into an issue with apt-get on the target board not being able to
find 'gpgv' to verify the signatures. This is installed as 'gpgv2' in the gnupg
recipe. Therefore I've used update-alternatives to create the appropriate link.

Whilst I was doing this, I felt it would be a good idea to replace the manual
creation of the 'gpg'->'gpg2' link in a do_install_append() function with proper
usage of update-alternatives.

This is my first attempt at using git send-email and submitting patches to
OpenEmbedded so if I've done anything wrong please point me in the right
direction.

Thanks,

-- 
Paul Barker

Email: paul at paulbarker.me.uk
http://www.paulbarker.me.uk