Replace the sample Calendar extension with a deprecation notice

Replace the sample Calendar extension with a deprecation notice linking to a
working (also By Google) Calendar extension.

BUG=435290
R=aboxhall@chromium.org
NOTRY=true

Committed: https://crrev.com/8a9227c890e05dd05adbebd00523222107e82919
Cr-Commit-Position: refs/heads/master@{#314075}

[aboxhall, 2015-02-01 00:32:02]

lgtm

[not at google - send to devlin, 2015-02-01 00:33:16]

The CQ bit was checked by kalman@chromium.org

[commit-bot: I haz the power, 2015-02-01 00:33:28]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/890173003/20001

[commit-bot: I haz the power, 2015-02-01 00:34:19]

Committed patchset #2 (id:20001)

[commit-bot: I haz the power, 2015-02-01 00:35:16]

Patchset 2 (id:??) landed as
https://crrev.com/8a9227c890e05dd05adbebd00523222107e82919
Cr-Commit-Position: refs/heads/master@{#314075}