heap-buffer-overflow in od_decode_haar_dc_level

[tysmith]

Found running commit 4633b81
Built with AddressSanitizer

To reproduce run:
./dump_video test_case.ogv

==47296==ERROR: AddressSanitizer: heap-buffer-overflow on address 0x625000004900 at pc 0x0000004fbf79 bp 0x7ffe84d2c220 sp 0x7ffe84d2c218
WRITE of size 4 at 0x625000004900 thread T0
    #0 0x4fbf78 in od_decode_haar_dc_level src/decode.c:690:48
    #1 0x4fbf78 in od_decode_recursive src/decode.c:805
    #2 0x4f61ad in od_decode_coefficients src/decode.c:979:9
    #3 0x4f61ad in daala_decode_packet_in src/decode.c:1204
    #4 0x4ec2de in main examples/dump_video.c:426:13
    #5 0x7f58f5c5f82f in __libc_start_main /build/glibc-GKVZIf/glibc-2.23/csu/../csu/libc-start.c:291
    #6 0x418f98 in _start (dump_video+0x418f98)

test_case.ogv.zip