Using git-svn with postreview.py causes binary diffs to be "hidden" -- i.e. reviewboard servers do not show that a binary file has been added/modified.  Prior to the patch, binary files would be represented in the diff as such:

Index: path/to/binary/file
===========================================
Binary files path/to/binary/file and path/to/binary/file differ



This change modifies that slightly so that the generated patches are more like svn:

Index: path/to/binary/file
===========================================
Cannot display: file marked as binary type.
svn:mime-type = application/octet-stream

New svn files also usually have a property associated with them -- this has been purposely omitted for simplicity.

Tested change against an RC 1.0 Beta 2 ReviewBoard instance with a 1.4 SVN server.  As expected, generated patches with this change reflected all image & audio asset changes/additions.  Without the patch, no asset changes were reflected.