doc: Add index for vdsm-infra package

Change-Id: I2cfc59ad59dbec52173d70ff320259cbdd95d77f
Signed-off-by: Dima Kuznetsov <dkuznets@redhat.com>
Reviewed-on: http://gerrit.ovirt.org/35917
Reviewed-by: Saggi Mizrahi <smizrahi@redhat.com>
Reviewed-by: Yeela Kaplan <ykaplan@redhat.com>
Reviewed-by: mooli tayer <mtayer@redhat.com>