Release note updates.
Release note updates.

Add item for last-minute CREATE INDEX CONCURRENTLY fix.
Repair a couple of misspellings of patch authors' names.

Back-branch updates will follow shortly, but I thought I'd
commit this separately just to make it more visible.

lisakowen/gpdb,50wu/gpdb,adam8157/gpdb,xinzweb/gpdb,xinzweb/gpdb,greenplum-db/gpdb,lisakowen/gpdb,lisakowen/gpdb,adam8157/gpdb,xinzweb/gpdb,lisakowen/gpdb,xinzweb/gpdb,xinzweb/gpdb,adam8157/gpdb,greenplum-db/gpdb,greenplum-db/gpdb,50wu/gpdb,lisakowen/gpdb,adam8157/gpdb,lisakowen/gpdb,50wu/gpdb,adam8157/gpdb,lisakowen/gpdb,xinzweb/gpdb,50wu/gpdb,adam8157/gpdb,greenplum-db/gpdb,xinzweb/gpdb,greenplum-db/gpdb,adam8157/gpdb,50wu/gpdb,greenplum-db/gpdb,50wu/gpdb,greenplum-db/gpdb,adam8157/gpdb,greenplum-db/gpdb,50wu/gpdb,50wu/gpdb,lisakowen/gpdb,xinzweb/gpdb