Use the system stdint.h on Windows in leveldatabase.

Skia wishes to use the system stdint.h on Windows. This is now possible
since VC2010 and later provide a stdint.h. VC2008 has been deprecated for
building Chromium (and Skia) for a full year now.

There are a number of stdint.h implementations in the codebase, some of
which hide others, and most of which are not complete (Skia needs
uintmax_t which most do not provide).

The stdint.h in leveldatabase/src/port/win is incomplete and is also
providing (apparently by accident) the stdint.h for Chromium's
src/content. As such, it is also hiding the system stdint.h from Skia
header files included in src/content.

The stdint.h in leveldatabase/src/port/win is also the only file in that
directory, so this change simply removes this directory from the list of
includes.

BUG=81490
R=jsbell@chromium.org

Review URL: https://codereview.chromium.org/27089002

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@228467 0039d316-1c4b-4281-b951-d872f2087c98
SVN changes up to revision 228467