Move an include guard to guard all code in base/move.h

Move an include guard to guard all code in base/move.h

gcc -H warned about base/move.h missing an include guard and it was
because the existing include guard didn't encompass all the code in the
file.

This fixes that warning and maybe makes compilations one nanosecond
faster.

The code outside the include guard was added Oct 2014 when fixing bug
418297.

BUG=418297
Committed: https://crrev.com/e67c6972f457f8d77d3b766f4dfb598e0a7be0e9
Cr-Commit-Position: refs/heads/master@{#325132}

[Daniel Bratell, 2015-04-14 16:17:47]

bratell@opera.com changed reviewers:
+ thakis@chromium.org

[Nico, 2015-04-14 16:50:03]

lgtm

[Nico, 2015-04-14 16:50:46]

The CQ bit was checked by thakis@chromium.org

[commit-bot: I haz the power, 2015-04-14 16:51:13]

CQ is trying da patch. Follow status at
 https://chromium-cq-status.appspot.com/patch-status/1082263002/1

[commit-bot: I haz the power, 2015-04-14 21:44:45]

Committed patchset #1 (id:1)

[commit-bot: I haz the power, 2015-04-14 21:46:04]

Patchset 1 (id:??) landed as
https://crrev.com/e67c6972f457f8d77d3b766f4dfb598e0a7be0e9
Cr-Commit-Position: refs/heads/master@{#325132}