[Telemetry] Fix flake in testVTuneProfiler.

[Telemetry] Fix flake in testVTuneProfiler.

Apparently at one point in time the GetCommandLine methods returned no
value for a missing process. Now it always returns a value or an
exception. So this code should be looking for the exception instead.

BUG=

Committed: https://crrev.com/2076b911427d5e212f09a2f84042a43717ee8384
Cr-Commit-Position: refs/heads/master@{#300044}

[tonyg, 2014-10-16 20:13:38]

tonyg@chromium.org changed reviewers:
+ dtu@chromium.org

[dtu, 2014-10-17 01:25:58]

The CQ bit was checked by dtu@chromium.org

[dtu, 2014-10-17 01:25:58]

lgtm

[commit-bot: I haz the power, 2014-10-17 01:26:56]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/659073005/1

[commit-bot: I haz the power, 2014-10-17 02:26:35]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2014-10-17 02:27:16]

Patchset 1 (id:??) landed as
https://crrev.com/2076b911427d5e212f09a2f84042a43717ee8384
Cr-Commit-Position: refs/heads/master@{#300044}