ECalBackendHttp: Remove the remove_sync() method.
ECalBackendHttp: Remove the remove_sync() method.

Cache reaper module takes care of the data and cache cleanup now.
When a data source is removed, the backend for it is simply finalized.

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