dxa: signal EOF

[ami_stuff]

autoexit does not work because EOF is not signalized

​http://samples.mplayerhq.hu/game-formats/dxa/meetsquid.dxa

C:\>ffplay -autoexit meetsquid.dxa
ffplay version N-46936-g8b6aeb1 Copyright (c) 2003-2012 the FFmpeg developers
  built on Nov 20 2012 19:34:37 with gcc 4.7.2 (GCC)
  configuration: --enable-gpl --enable-version3 --disable-pthreads --enable-runt
ime-cpudetect --enable-avisynth --enable-bzlib --enable-frei0r --enable-libass -
-enable-libopencore-amrnb --enable-libopencore-amrwb --enable-libfreetype --enab
le-libgsm --enable-libmp3lame --enable-libnut --enable-libopenjpeg --enable-libo
pus --enable-librtmp --enable-libschroedinger --enable-libspeex --enable-libtheo
ra --enable-libutvideo --enable-libvo-aacenc --enable-libvo-amrwbenc --enable-li
bvorbis --enable-libvpx --enable-libx264 --enable-libxavs --enable-libxvid --ena
ble-zlib
  libavutil      52.  8.100 / 52.  8.100
  libavcodec     54. 74.100 / 54. 74.100
  libavformat    54. 37.100 / 54. 37.100
  libavdevice    54.  3.100 / 54.  3.100
  libavfilter     3. 23.101 /  3. 23.101
  libswscale      2.  1.102 /  2.  1.102
  libswresample   0. 17.101 /  0. 17.101
  libpostproc    52.  2.100 / 52.  2.100
[dxa @ 02af0060] max_analyze_duration 5000000 reached at 5034014
Input #0, dxa, from 'meetsquid.dxa':
  Duration: 00:00:44.40, start: 0.000000, bitrate: 356 kb/s
    Stream #0:0: Video: dxa, pal8, 640x480, 10 fps, 10 tbr, 10 tbn, 10 tbc
    Stream #0:1: Audio: adpcm_ms ([2][0][0][0] / 0x0002), 11025 Hz, 1 channels,
s16, 44 kb/s
Frame changed from size:0x0 to size:640x480
  47.98 A-V:  2.192 fd=   0 aq=    0KB vq=    0KB sq=    0B f=0/0

[Carl Eugen Hoyos]

Fixed by you.