[INTERNAL] changed visibility of fields in Const.WatchdogClient

Made the remaining protected fields private.

Change-Id: Ifa8944b8a46320311aa9dc5e1e6a2d2a35a19be3
Reviewed-on: http://saros-build.imp.fu-berlin.de/gerrit/1884
Tested-by: Jenkins CI
Reviewed-by: Stefan Rossbach <srossbach@arcor.de>