Update release metadata for 2.4.3

Change-Id: I3158f023a6292bcb6b63df5b92c60a6835b592cc
Reviewed-on: http://review.couchbase.org/42325
Tested-by: Mark Nunberg <mnunberg@haskalah.org>
Reviewed-by: Sergey Avseyev <sergey.avseyev@gmail.com>