If value meta length is larger than the size of the Vertica column,
the write will fail and cause the persister to die. Check the length
and drop the value meta if too large. This should not occur as the
value meta is validated by the API before being written to Kafka,
but this is a cheap check and ensures the persister will stay up if
some application starts writing directly to the Kafka queue
Change-Id: I893d02751217beb6ba5a88625f20448c45a1b376
0529f0ca3a