Fix path in components_tests.gyp to GN version of components_unittests

Fix path in components_tests.gyp to GN version of components_unittests

There was a typo where a '/' was used instead of a ':'.  components_unittests
is found in components/BUILD.gn.

Committed: https://crrev.com/9f8fae1fae0003f5544f0888ac64408c33ed10bd
Cr-Commit-Position: refs/heads/master@{#316582}

[mstrum, 2015-02-16 18:33:00]

mstrum@amazon.com changed reviewers:
+ blundell@chromium.org

[mstrum, 2015-02-16 18:33:00]

PTAL

[blundell, 2015-02-17 08:24:46]

lgtm

[mstrum, 2015-02-17 16:20:44]

The CQ bit was checked by mstrum@amazon.com

[commit-bot: I haz the power, 2015-02-17 16:21:12]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/931653002/1

[commit-bot: I haz the power, 2015-02-17 16:40:11]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-02-17 16:40:46]

Patchset 1 (id:??) landed as
https://crrev.com/9f8fae1fae0003f5544f0888ac64408c33ed10bd
Cr-Commit-Position: refs/heads/master@{#316582}