Log Message:
Updated distcc to 2.15

* Fix crash bug in receiving LZO compressed data into a mmapped file.
* Remove redundant temporary file cleanup in non-forking mode.
* Client calculates and can display the overall throughput in preprocessed
  bytes per second for remote jobs.
* The deprecated fork-after-exec mode controlled by the --no-prefork option
  has been removed.
* mmap is no longer used for compressed data to simplify the code.
* Daemon now chdirs to $TMPDIR at startup rather than /. This allows dumping
  core, among other things.