Revert 238671 "Added net::NetworkInterface::interface_index."

Speculative revert to see if it fixes the issues with net_unittests
on WinXP: http://build.chromium.org/p/chromium.win/builders/XP%20Tests%20%282%29/builds/32133/steps/net_unittests/logs/stdio

> Added net::NetworkInterface::interface_index.
> Not implemented for Android.
> 
> BUG=319068
> 
> Review URL: https://codereview.chromium.org/100703002

TBR=vitalybuka@chromium.org

Review URL: https://codereview.chromium.org/101403004

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@238707 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 238707