remove comments
fetch catalog.json while joining to cluster
fix bug
fix bug
refactor
Merge pull request #12 from long-long-float/share-catalog-automatically

Fetch catalog.json from the source replica node, by the joining node itself.

 * Fetch catalog.json via "catalog.fetch" Droonga command.
 * Remove needless codes to read local catalog.json by droonga-engine-join command.