Telemetry: Simplify exception handling of failed websocket connections.

Telemetry: Simplify exception handling of failed websocket connections.

Previously, an intermediary exception InspectorException was generated. This
was caught and then converted into a more common Telemetry exception. Now the
connection failure throws a standard Telemetry exception directly.

BUG=460625
Committed: https://crrev.com/b18d23f7330a6d01dd7dda7f5bc4713fdc470afe
Cr-Commit-Position: refs/heads/master@{#319161}

[erikchen, 2015-02-28 00:56:45]

erikchen@chromium.org changed reviewers:
+ nednguyen@google.com

[erikchen, 2015-02-28 00:56:46]

nednguyen: Please review.

[nednguyen, 2015-03-04 00:20:22]

nednguyen@google.com changed reviewers:
+ dtu@chromium.org, sullivan@chromium.org

[sullivan, 2015-03-04 14:38:52]

lgtm

[erikchen, 2015-03-04 22:15:01]

The CQ bit was checked by erikchen@chromium.org

[commit-bot: I haz the power, 2015-03-04 22:17:08]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/955263003/20001

[commit-bot: I haz the power, 2015-03-04 23:22:53]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-03-04 23:23:59]

Patchset 2 (id:??) landed as
https://crrev.com/b18d23f7330a6d01dd7dda7f5bc4713fdc470afe
Cr-Commit-Position: refs/heads/master@{#319161}