E.46.1. Migration to version 7.4.5

A dump/restore is not required for those running 7.4.X.

E.46.2. Changes

• Repair possible crash during concurrent B-tree index insertions

  This patch fixes a rare case in which concurrent insertions into a B-tree index could result in a server panic. No permanent damage would result, but it's still worth a re-release. The bug does not exist in pre-7.4 releases.