PersonalDataManager: Update server address metadata in the server DB

...instead of in the local DB.
For full-Sync users, the two DBs are identical anyway, so this is a
no-op. But for Sync-transport-only users, using the server DB is the
correct thing to do. Also note that another UpdateServerAddressMetadata
call (from ConvertWalletAddressesToLocalProfiles) already uses the
server DB.

Bug: 864519
Change-Id: I67d8248fa59453b4bbbe63fb90d2ab46adc745ce
Reviewed-on: https://chromium-review.googlesource.com/c/1474665
Reviewed-by: Fabio Tirelo <ftirelo@chromium.org>
Commit-Queue: Marc Treib <treib@chromium.org>
Cr-Commit-Position: refs/heads/master@{#633675}