Fixing Issue #319

Fixing Issue #319 preventing unoconv from being installed in CentOS. I am not sure if "_with_openoffice2" needs changing too.
Icinga: Update to 1.11.0, mailinglists, download url.
Icinga Web: Update to 1.11.0, mailinglists, download url.
Merge pull request #324 from nikosp77/patch-2

Fixing Issue #319
icinga: Update icinga.spec: groupadd

Updated groupadd steps to use -r like the useradd step already does. This creates the groups as system groups instead of user groups.
Merge pull request #330 from hoag/patch-1

icinga: Update icinga.spec: groupadd
Update libserf to 1.1.1.