More fixes to hooks documentation
More fixes to hooks documentation

Signed-off-by: David Knowles <bbb6da7cc32f17ff336b51a2d5b7c5c403d95058@google.com>
Signed-off-by: Iustin Pop <acf83a5274f31a43af6b914614365999469c1a31@google.com>
Reviewed-by: Iustin Pop <acf83a5274f31a43af6b914614365999469c1a31@google.com>

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