Bug 1120467: Fixing wrong grep format for threaddump in ruby-2.0

Problem was that ruby-1.8 and 1.9 Rack processes which are grepped upon the threaddump action look like:
`Rack: /var/lib/openshift/53c910b204a1bbc98f00001d/app-root/runtime/repo`,
whereas the ruby-2.0 process looks like:
`Passenger RackApp: /var/lib/openshift/53c911e304a1bbfca7000001/app-root/runtime/repo`

Just modified the grepped string