Make sure to initialize fd_sets in aio.c

This was spotted by valgrind.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>



git-svn-id: svn://svn.savannah.nongnu.org/qemu/trunk@5470 c046a42c-6fe2-441c-8c8c-71466251a162
