For the block cache to be shared between column families, the options
instance must be shared between the various column families being
created. This also ensures that there is only one source of truth for
configuration options instead of having two different sets depending on
how the tables were initialized.
This PR also removes the re-opening mechanism which can double startup
time - every time the database is opened, the log is replayed - a large
log file will take a long time to open.
Finally, several options got correclty implemented as column family
options, including an one that puts a hash index in the SST files.
41cf81f80b