[Sync] Fix error handling during startup scenarios

[Sync] Fix error handling during startup scenarios

Two cases are now improved:
1. Errors during model loading. Previously this would trigger a reconfiguration
despite being in the middle of an existing configuration.

2. Errors after model loading but before association. Previously these would do
nothing.

BUG=415757
Committed: https://crrev.com/2a445408e65baff94fb748f03ce30f76e09c60bc
Cr-Commit-Position: refs/heads/master@{#296011}

[Nicolas Zea, 2014-09-19 00:22:44]

Patchset #2 (id:20001) has been deleted

[Nicolas Zea, 2014-09-19 20:17:44]

zea@chromium.org changed reviewers:
+ maniscalco@chromium.org

[Nicolas Zea, 2014-09-19 20:17:44]

PTAL

[maniscalco, 2014-09-22 16:52:01]

lgtm

[Nicolas Zea, 2014-09-22 17:09:20]

The CQ bit was checked by zea@chromium.org

[commit-bot: I haz the power, 2014-09-22 17:10:55]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/585643003/60001

[commit-bot: I haz the power, 2014-09-22 18:09:22]

Committed patchset #3 (id:60001) as 5dcd4a0309cede8ef62b8053a4e14e8342da15a8

[commit-bot: I haz the power, 2014-09-22 18:09:56]

Patchset 3 (id:??) landed as
https://crrev.com/2a445408e65baff94fb748f03ce30f76e09c60bc
Cr-Commit-Position: refs/heads/master@{#296011}