KolabMailImapClient: adapted to Camel changes
KolabMailImapClient: adapted to Camel changes

* removed inclusion of individual camel header
* use new uidvalidity getter function from
  libekolabutil
* removed unused symbol
* pass GCancellable on to CamelService
  connect/disconnect functions

GNOME/evolution-kolab,GNOME/evolution-kolab