Fixes: Signal connection warnings due to flick gesture and key overrides
Fixes: Signal connection warnings due to flick gesture and key overrides

RevBy: Jan Arne Petersen
Details: Removed the connections in MKeyboardHost that were bound to already
removed slots. Also fixed the warning for key overrides, which was actually a
connection leak.

maliit/plugins,KDE/plasma-maliit-plugins,RHawkeyed/plugins,develersrl/maliit-demo-qml,KDE/plasma-maliit-plugins,RHawkeyed/plugins,maliit/plugins,develersrl/maliit-demo-qml,RHawkeyed/plugins,develersrl/maliit-demo-qml,develersrl/maliit-demo-qml,KDE/plasma-maliit-plugins,maliit/plugins,RHawkeyed/plugins,KDE/plasma-maliit-plugins,RHawkeyed/plugins,maliit/plugins