#2401 fix typo in add column statement

git-svn-id: http://svn.osgeo.org/postgis/branches/2.1@11721 b70326c6-7e19-0410-871a-916f4a2858ee
#2401 What was I thinkng.  pagc_rules needs to set existing to is_custom = false so old records are not considered custom

git-svn-id: http://svn.osgeo.org/postgis/branches/2.1@11722 b70326c6-7e19-0410-871a-916f4a2858ee
#2401 logic to mark pagc_rules as editable and for backup save custom rules

git-svn-id: http://svn.osgeo.org/postgis/branches/2.1@11723 b70326c6-7e19-0410-871a-916f4a2858ee