Update installation_others.rst

I think we don't need to define access.log and error.log since owncloud does the logging automatically in /var/log/access.log and /var/log/error.log. Setting a log level here would even rule out the gui setting in the admin section of owncloud.

…and some little design fixes.
Merge pull request #76 from ThomasKramps/patch-2

Update installation_others.rst