This patch locks down search_path in extension install and update
scripts to only contain pg_catalog, this requires that any reference
in those scripts is fully qualified. Additionally we add explicit
create commands to all update scripts for objects added to the
public schema. This change will make update scripts fail if a
function with identical signature already exists when installing
or upgrading instead reusing the existing object.
Primary and unqiue constraints are limited to segment_by and order_by
columns and foreign key constraints are limited to segment_by columns
when creating a compressed hypertable. There are no restrictions on
check constraints.
