[CamelService] Connect/Disconnect rely on provided cancellable
[CamelService] Connect/Disconnect rely on provided cancellable

To properly react on Connect and Disconnect requests the cancellable
for these should be provided, because the code relies on it and uses
it to eventually cancel any pending connect or disconnect, but
the cancellable is an optional parameter, thus always create one
if necessary.

matzipan/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,matzipan/evolution-data-server,tintou/evolution-data-server,tintou/evolution-data-server,tintou/evolution-data-server,matzipan/evolution-data-server