To use LevelDB, follow these steps:

1) In the SConstruct file, change
	LevelDB = bool(0)
to
	LevelDB = bool(1)

2) Compile with 'scons'.

3) If you have no databases you care about, remove them. Otherwise, start
rippled with '--import' to import your existing hashnode database into
LevelDB. After you import the hashnode database, either delete (or move) the
'hashnode.db', 'hashnode.db-shm' and 'hashnode.db-wal' files from your
database directory. Do not touch the LevelDB files in the 'hashnode'
directory.