gpu/khronos_glcts_support: use override specifier

gpu/khronos_glcts_support: use override specifier

Annotate the base class override functions with the
override specifier to appease the chromium-style
checker.

BUG=chromium:412865
R=kbr@chromium.org, piman@chromium.org, dpranke@chromium.org
TEST=Verify khronos_glcts_test builds and runs

Signed-off-by: U. Artie Eoff <ullysses.a.eoff@intel.com>;

Committed: https://crrev.com/93489a38d20cc3c877d6362edbe779e76b6c6623
Cr-Commit-Position: refs/heads/master@{#356710}

[Dirk Pranke, 2015-10-28 23:47:24]

I defer this one to kbr or piman.

[piman, 2015-10-29 00:09:39]

lgtm

[U. Artie Eoff, 2015-10-29 00:28:41]

The CQ bit was checked by ullysses.a.eoff@intel.com

[commit-bot: I haz the power, 2015-10-29 00:29:18]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1412793010/20001
View timeline at
 https://chromium-cq-status.appspot.com/patch-timeline/1412793010/20001

[Ken Russell (switch to Gerrit), 2015-10-29 00:36:20]

Thanks. LGTM after the fact.

[commit-bot: I haz the power, 2015-10-29 00:55:05]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-10-29 00:55:50]

Patchset 2 (id:??) landed as
https://crrev.com/93489a38d20cc3c877d6362edbe779e76b6c6623
Cr-Commit-Position: refs/heads/master@{#356710}