Eliminate RABBITMQ_PLUGINS_EXPAND_DIR

There were a number of issues with RABBITMQ_PLUGINS_EXPAND_DIR:

- It was undocumented in the context of the generic unix package, and
  if unwisely set could do an effective "rm -rf" in an unintended
  location.

- It did not take account of the possibility that multiple nodes could
  be starting at once, and so doing plugins activation
  simultanteously.

Instead, use RABBITMQ_MNESIA_DIR/plugins-scratch.  This avoids the
need to extend the generic unix package documentation, the location is
node-specific, and the distinctive plugins-scratch subdirectory
reduces the risk of unintended file deletions.
(transplanted from 064b8797493bb290156fb72a54f9e9276df0faed)

0 files changed, 0 insertions, 0 deletions