When doing svn copy, or svn mv, a SynthenticAdditionDiff is generated.
If the path is a directory, an error will occur when checking the
mime-type of the directory. Immediately after the properties check,
the function returns null if the path is a directory. Move this
check to before the properties check to avoid exiting with an error.
Command failed with error #1! COMMAND svn propget 'svn:mime-type' '/home/trasz/svn/ports/cad/py-pycam'@ STDOUT (empty) STDERR svn: warning: W200017: Property 'svn:mime-type' not found on '/home/trasz/svn/ports/cad/py-pycam@' svn: E200000: A problem occurred; see other errors for details (Run with `--trace` for a full exception trace.)