Repair should re-create missing collection data files from the existing metadata

When running mongodb with --repair and find that verify returns ENOENT (no such file), we can safely drop the WiredTiger table and re-create it with the same metadata creation string as the original.

The metadata for the ident can be read in with a "metadata:create" cursor before dropping the table.

This should also handle the case the when a collection is missing when started with --directoryperdb.