Compiling with GCC 4.6.0 20100925 produced warnings like:
/src/qemu/net/tap-win32.c: In function 'tap_win32_open':
/src/qemu/net/tap-win32.c:582:12: error: variable 'hThread' set but not used [-Werror=unused-but-set-variable]

Fix by removing the unused variables.

Signed-off-by: Blue Swirl <blauwirbel@gmail.com>