silence has_changed_character may be used uninitialized warning

silence has_changed_character may be used uninitialized warning

Some slightly older versions of gcc aren't clever enough to figure out
that this variable won't be used if the return value from the function
that initializes it is false.  Tested with gcc 4.5.1.

R=yangguo@chromium.org

Committed: https://code.google.com/p/v8/source/detail?r=18456

[Mostyn Bramley-Moore, 2013-12-24 14:51:39]

@Yang: PTAL at this tiny patch.

[Yang, 2013-12-24 15:26:03]

LGTM. I'll land this after the holidays.

[Mostyn Bramley-Moore, 2013-12-24 16:15:56]

Thanks.  No rush, have a good break :)

[Yang, 2014-01-03 20:11:54]

Benedikt, could you please help me land this patch? It looks like I won't be
able to do this anytime soon. Thanks!

[Benedikt Meurer, 2014-01-04 18:18:54]

On 2014/01/03 20:11:54, Yang wrote:
> Benedikt, could you please help me land this patch? It looks like I won't be
> able to do this anytime soon. Thanks!

Sure, I'll land it.

[Benedikt Meurer, 2014-01-04 18:20:56]

Committed patchset #1 manually as r18456.