Fixes issues around the same database being created in parallel.

When 2 or more HiveTaps try to write to tables in the same database they
might end up trying to create the same database multiple times which
will cause an SQL constraint violation exception that breaks the
job. This commit catches that particular exception and swallows it.
I have to agree this cause is a little confusing. Can we split it into a named method so that the meaning is instantly clear?
```
catch( MetaException ex )
  {
  // comment explaining why it's ok to ignore exceptions caused by writing to the same database
  if ( !databaseConcurrentlyCreated(ex) )
    {
    throw ex
    }
  }

  // later ...
boolean databaseConcurrentlyCreated(ex: Exception) {
  return ex.getCause() != null && ex.getCause().getCause() != null && etc ...
}
```