[r=axwalk] state: reduce default dial timeout to 30s
Previously we could have been dialling state connections across the Internet, since the CLI would connect to Mongo directly. Now, with the CLI going to API only, we can safely reduce the timeout.
It is possible that the timeout will be exceeded if the peers in an HA setup are not all ready. In this case the dial operation will fail and the caller (state server agent) will restart.
This change will reduce the time to failure in tests, and allow us to capture some information about the failed test without exceeding the Go test timeout.