Info about enabling and disabling a service included in admin guide

Included section to enable and disable a service. Also included a note
about the new '--reason' parameter for Compute which allows user to
log a reason for disabling a service.

Change-Id: I5522d31e6d14147296a4eeee1bc4df5e9d5e0b75
Section about anonymous users applies to openSUSE

This section is valid for openSUSE as well.

Remove some whitespace.

Change-Id: Ic5264254f4434aee6da053a6b2de785daadf7045
Merge "Info about enabling and disabling a service included in admin guide"