subdir: use util.dump and util.load for writing and reading We need to change both svnmeta and svncommands at the same time since they are heavily tied together. The reason for this change is to remove the duplicate code for reading and writing subdir present in svncommands.py. We will now use the standard util.dump and util.load for writing and reading. Due to the way json reads a string, the old format is still valid for use and will be read correctly.