[Google backend] Claim Contacts and Tasks in populate()
[Google backend] Claim Contacts and Tasks in populate()

If not done, then the old ESource-s could be forgotten and a new added,
despite the old being available, which has consequences like local
cache of these ESource-s re-population and similar.

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