base1: Fix D-Bus watch tests
base1: Fix D-Bus watch tests

Similarly to commit dc2aaff1ab82c26898, the other two D-Bus watch tests
need a deep update of the cache as well. After commit 4e5a309f0af the
order of the messages changed (often), and we could get the "empty"
state updates after the "real" one.

martinpitt/cockpit,mvollmer/cockpit,cockpit-project/cockpit,cockpit-project/cockpit,mvollmer/cockpit,garrett/cockpit,cockpit-project/cockpit,mvollmer/cockpit,garrett/cockpit,garrett/cockpit,martinpitt/cockpit,cockpit-project/cockpit,martinpitt/cockpit,martinpitt/cockpit,martinpitt/cockpit,mvollmer/cockpit,garrett/cockpit,garrett/cockpit,cockpit-project/cockpit,mvollmer/cockpit