Remove 'datlastsysoid'.

It hasn't been used for anything for a long time. Up until recently,
we still queried it when dumping very old servers, but since
commit 30e7c175b8, there's no longer any
code at all that cares about it.

Discussion: http://postgr.es/m/CA+Tgmoa14=BRq0WEd0eevjEMn9EkghDB1FZEkBw7+UAb7tF49A@mail.gmail.com

doc/src/sgml/bki.sgml

@@ -183,7 +183,7 @@
   descr => 'database\'s default template',
   datname => 'template1', encoding => 'ENCODING', datcollate => 'LC_COLLATE',
   datctype => 'LC_CTYPE', datistemplate => 't', datallowconn => 't',
-  datconnlimit => '-1', datlastsysoid => '0', datfrozenxid => '0',
+  datconnlimit => '-1', datfrozenxid => '0',
   datminmxid => '1', dattablespace => 'pg_default', datacl => '_null_' },
 
 ]

doc/src/sgml/catalogs.sgml

@@ -3001,16 +3001,6 @@ SCRAM-SHA-256$<replaceable>&lt;iteration count&gt;</replaceable>:<replaceable>&l
       </para></entry>
      </row>
 
-     <row>
-      <entry role="catalog_table_entry"><para role="column_definition">
-       <structfield>datlastsysoid</structfield> <type>oid</type>
-      </para>
-      <para>
-       Last system OID in the database; useful
-       particularly to <application>pg_dump</application>
-      </para></entry>
-     </row>
-
      <row>
       <entry role="catalog_table_entry"><para role="column_definition">
        <structfield>datfrozenxid</structfield> <type>xid</type>

doc/src/sgml/ecpg.sgml

@@ -4732,7 +4732,6 @@ encoding = 0 (type: 5)
 datistemplate = t (type: 1)
 datallowconn = t (type: 1)
 datconnlimit = -1 (type: 5)
-datlastsysoid = 11510 (type: 1)
 datfrozenxid = 379 (type: 1)
 dattablespace = 1663 (type: 1)
 datconfig =  (type: 1)
@@ -4757,7 +4756,6 @@ encoding = 0 (type: 5)
 datistemplate = f (type: 1)
 datallowconn = t (type: 1)
 datconnlimit = -1 (type: 5)
-datlastsysoid = 11510 (type: 1)
 datfrozenxid = 379 (type: 1)
 dattablespace = 1663 (type: 1)
 datconfig =  (type: 1)