When the contact chore starts running before the monitor service has
provided any useful capacity data, the first outgoing contact has
not-very-helpful data for the satellite. This change causes the contact
chore to wait until capacity data is available. The wait should be quite
short in all reasonable cases: even when a node starts with a lot of
stored pieces and no cached spaceUsedDB data, new data will have been
calculated and cached by the call to
`peer.Storage2.CacheService.Init(ctx)` in `storagenode.cmdRun()` before
`peer.Run(ctx)`.
Change-Id: Ibc26d5c1fc10a23006c00bc3f13ff6cf71f8bf1d
1469f7f41f