Clang update script: disable --with-android with LLVM_FORCE_HEAD_REVISION

Clang update script: disable --with-android with LLVM_FORCE_HEAD_REVISION

Unless we're targeting Android, Linux builders don't have the NDK checked
out.

BUG=452726
NOTRY=true

Committed: https://crrev.com/d4f844473bd590970dc46c8c6ead8c3d9a7687d2
Cr-Commit-Position: refs/heads/master@{#316316}

[hans, 2015-02-13 22:41:27]

hans@chromium.org changed reviewers:
+ thakis@chromium.org

[hans, 2015-02-13 22:41:28]

Please take a look.

I first tried to configure the builder to set target_os=android when calling
gclient, but it seemed very hard to do that without actually making the build
target android.

[Nico, 2015-02-13 22:45:34]

lgtm

[hans, 2015-02-13 22:48:02]

The CQ bit was checked by hans@chromium.org

[commit-bot: I haz the power, 2015-02-13 22:48:53]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/927703002/20001

[hans, 2015-02-13 22:57:36]

The CQ bit was unchecked by hans@chromium.org

[hans, 2015-02-13 22:58:02]

The CQ bit was checked by hans@chromium.org

[hans, 2015-02-13 22:59:22]

The CQ bit was unchecked by hans@chromium.org

[hans, 2015-02-13 23:05:13]

The CQ bit was checked by hans@chromium.org

[commit-bot: I haz the power, 2015-02-13 23:06:47]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/927703002/20001

[commit-bot: I haz the power, 2015-02-13 23:08:34]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-13 23:09:18]

Patchset 2 (id:??) landed as
https://crrev.com/d4f844473bd590970dc46c8c6ead8c3d9a7687d2
Cr-Commit-Position: refs/heads/master@{#316316}