syncbase/vsync: SyncGroup membership view.

Create a view of all SyncGroup members and refresh it on a timeout.
Scan the SyncGroups in each database across all apps.

Additional fixes from previous CLs:
- Switch to using verror.
- Reuse the existing random number generator.
- Assert that a store.Transaction is passed where it is required.
- Improve some comments.

Change-Id: I69bbed808c3b91f38f8f11bef51865b38736651f
5 files changed
tree: ddecc88dd182ca5f76a872f3d9e0769125691ffb
  1. v23/
  2. x/
  3. .gitignore
  4. AUTHORS
  5. CONTRIBUTORS
  6. LICENSE
  7. PATENTS
  8. VERSION