editor: correctly import symlink copy+modify with non-empty prefix We alwasy fail editing for symlinks, since we strip the leading 'link ' subversion includes when storing in mercurial, and then let svn attempt to apply deltas against the stripped version. This unsurprisingly fails, and we write the resulting empty-string to the Filestore for the current revision, and add the symlink in question to the missing list to handle stupidly later. Unfortunately, this would break down because editing adds files to the store using their absolute path whereas missing files are added relative to our subdir. the absolut path file appears to win, which results in us getting a symlink whose target is the empty string. This fixes the problem by adding missing files to the fileStore using their absolute path.