Don't override _HAS_TR1 on VS > 2008

When building with VS 2010, causes warnings like:

c:\Program Files (x86)\Microsoft Visual Studio 10.0\VC\INCLUDE\yvals.h(21) : warning C4005: '_HAS_TR1' : macro redefinition
        command-line arguments :  see previous definition of '_HAS_TR1'

(This is the same change that was made in Chromium's common.gypi)

BUG=125606
r8503

[krasin, 2012-05-01 21:49:24]

Nick,

could you please take a look?

Thanks,
Ivan Krasin

[noelallen_use_chromium, 2012-05-01 22:53:17]

LGTM

[commit-bot: I haz the power, 2012-05-01 22:54:26]

CQ is trying da patch. Follow status at
https://nativeclient-status.appspot.com/cq/scottmg@chromium.org/10264015/1

[commit-bot: I haz the power, 2012-05-01 23:18:40]

The commit queue went berserk retrying too often for a
seemingly flaky test. Builder is nacl-arm_hw_opt_panda, revision is 8470, job
name
was 10264015-1 (retry) (retry) (retry) (retry).

[M-A Ruel, 2012-05-01 23:52:29]

The CQ for NaCl is broken until someone fixes it.

[scottmg, 2012-05-02 19:36:55]

I tried to dcommit, but got "Authorization failed: Authorization failed at
c:\src\depot_tools\git_bin/libexec/git-core/git-svn line 4441". (svn ls ...
works OK).

The commit bit a different set of people than Chromium I guess?

[Nico, 2012-05-04 18:25:01]

Landed in r8503