Fix formatting of commands

After my last changes the formatting of one block of commands was different.
Fix it.
Insert new heading for section 9 and renumber following sections

The new section describes the format upgrade, which was formerly part of the section "start imap".
add new section 9 "prepare environment variables" and renumber following sections

The example commands use variables as placeholders for cyrus-admin user, password, etc.
We read these values from /etc/kolab/kolab.conf so we can cut&paste the following commands.

After insertion of the preparation section we need to renumber the following sections (again).
Merge pull request #26 from jh23453/patch-3

Updates to upgrade guide