mediagoblin 0.9, media-type video enabled

Steps to reproduce

1. Start a local ./lazyserver.sh .
2. Access an uploaded video file.

The page is shown correctly, it is possible to watch the video, but the log reads:

2017-02-09 09:12:15,067 ERROR   [waitress] Exception when serving /mgoblin_media/media_entries/13/....webm           
Traceback (most recent call last):
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/channel.py", line 338, in service                                           
    task.service()
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/task.py", line 169, in service                                              
    self.execute()
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/task.py", line 437, in execute                                              
    self.write(chunk)
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/task.py", line 303, in write                                                
    channel.write_soon(towrite)
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/channel.py", line 320, in write_soon                                        
    self.outbufs[-1].append(data)
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/buffers.py", line 242, in append
    buf.append(s)
  File "/srv/mediagoblin.latest/lib/python2.7/site-packages/waitress-1.0.2-py2.7.egg/waitress/buffers.py", line 53, in append
    read_pos = file.tell()
ValueError: I/O operation on closed file

The error was solved by running ./bin/gmg dbupdate

Steps to Reproduce (master branch) ./bootstrap && ./configure --with-python3 && make ./lazyserver Basic server functions work fine like user login (after created with gmg) and browsing gmg added media. However once logged in clicking the "add media" button or going to /submit/ causes a ValueError: too many values to unpack (expected 2) with a stacktrace ​https://paste.gnome.org/pcqsu0kc0 Keeping priority as major because not being able to add video files is essential to the program.

Need to test out new media_type plugins in #723.

At a bare minimum, audio and video support, but all media types would be nice.

Thanks simonft