heap-buffer-overflow in od_bin_fdct64

[tysmith]

Found running commit 4633b81
Built with AddressSanitizer

To reproduce run:
./dump_video test_case.ogv

==46934==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x63400007e800 at pc 0x0000005783b0 bp 0x7ffd5098ff00 sp 0x7ffd5098fef8
READ of size 4 at 0x63400007e800 thread T0
    #0 0x5783af in od_bin_fdct64 src/dct.c:4519:8
    #1 0x56fc9e in od_bin_fdct64x64 src/dct.c:4910:28
    #2 0x4fc5a2 in od_block_decode src/decode.c:519:7
    #3 0x4faf86 in od_decode_recursive src/decode.c:782:5
    #4 0x4f61ad in od_decode_coefficients src/decode.c:979:9
    #5 0x4f61ad in daala_decode_packet_in src/decode.c:1204
    #6 0x4ec2de in main examples/dump_video.c:426:13
    #7 0x7f588c87282f in __libc_start_main /build/glibc-GKVZIf/glibc-2.23/csu/../csu/libc-start.c:291
    #8 0x418f98 in _start (dump_video+0x418f98)

test_case.ogv.zip