AR: fixed postgres fixture tests [#4519 state:resolved]

Signed-off-by: NJeremy Kemper <jeremy@bitsweat.net>

activerecord/lib/active_record/fixtures.rb

@@ -516,7 +516,7 @@ def self.create_fixtures(fixtures_directory, table_names, class_names = {})
             # Cap primary key sequences to max(pk).
             if connection.respond_to?(:reset_pk_sequence!)
               table_names.each do |table_name|
-                connection.reset_pk_sequence!(table_name)
+                connection.reset_pk_sequence!(table_name.tr('/', '_'))
               end
             end
           end