Remove obsolete Debian-related documentation
Remove obsolete Debian-related documentation

This part of the documentation refers to Grub instead of Grub2, but
Grub2 has been the standard boot loader since Squeeze. As this part only
(wrongly) repeats the preceeding documentation, it's removed completely.

Signed-off-by: Thomas Thrainer <98bdeac947eb8ca18146e9ce7f092788ec242cd1@google.com>
Reviewed-by: Guido Trotter <f62ca4d5358bdaeef0e50e57f9f7e231de63727e@google.com>

ganeti/ganeti,yiannist/ganeti,yiannist/ganeti,grnet/snf-ganeti,grnet/snf-ganeti,ganeti-github-testing/ganeti-test-1,andir/ganeti,apyrgio/snf-ganeti,apyrgio/snf-ganeti,mbakke/ganeti,mbakke/ganeti,ganeti-github-testing/ganeti-test-1,bitemyapp/ganeti,andir/ganeti,leshchevds/ganeti,dimara/ganeti,onponomarev/ganeti,leshchevds/ganeti,bitemyapp/ganeti,andir/ganeti,yiannist/ganeti,dimara/ganeti,apyrgio/ganeti,mbakke/ganeti,apyrgio/ganeti,leshchevds/ganeti,ganeti/ganeti,onponomarev/ganeti,ganeti/ganeti