Fix FDW for PostgreSQL 11

In PG 11, `table_type` changed from 'FOREIGN TABLE' to 'FOREIGN'.
This commit avoids that difference entirely.

ee/lib/gitlab/geo/fdw.rb

@@ -37,10 +37,9 @@ module Gitlab
           Gitlab::Geo.cache_value(:geo_fdw_count_tables) do
             sql = <<~SQL
               SELECT COUNT(*)
-                FROM information_schema.tables
-               WHERE table_schema = '#{FOREIGN_SCHEMA}'
-                 AND table_type = 'FOREIGN TABLE'
-                 AND table_name NOT LIKE 'pg_%'
+                FROM information_schema.foreign_tables
+               WHERE foreign_table_schema = '#{FOREIGN_SCHEMA}'
+                 AND foreign_table_name NOT LIKE 'pg_%'
             SQL
 
             ::Geo::TrackingBase.connection.execute(sql).first.fetch('count').to_i