Update man page of ipa-server-install
This fix adds information about --ignore-last-of-role in
ipa-server-install man page
Fixes https://fedorahosted.org/freeipa/ticket/6634
Signed-off-by: Abhijeet Kasurde <akasurde@redhat.com>
Reviewed-By: Stanislav Laznicka <slaznick@redhat.com>