Prepare the NEWS file for 2.13.0~beta1
Prepare the NEWS file for 2.13.0~beta1

This patch adds a few previously unmentioned features and issues to the
2.13 notes, and sets the release date.

Signed-off-by: Hrvoje Ribicic <be5828fca31f89218048bec4189e30a581aa65da@google.com>
Reviewed-by: Klaus Aehlig <4ce51de36d9068cd7db2eec1151e0f3f95419008@google.com>

yiannist/ganeti,mbakke/ganeti,yiannist/ganeti,yiannist/ganeti,andir/ganeti,mbakke/ganeti,ganeti/ganeti,leshchevds/ganeti,leshchevds/ganeti,dimara/ganeti,onponomarev/ganeti,ganeti/ganeti,dimara/ganeti,leshchevds/ganeti,onponomarev/ganeti,ganeti/ganeti,mbakke/ganeti,andir/ganeti,bitemyapp/ganeti,andir/ganeti,bitemyapp/ganeti,grnet/snf-ganeti,grnet/snf-ganeti