On 4xx we have to return an empty response instead of an exception

server/extension/Makefile

@@ -13,8 +13,8 @@ OLD_VERSIONS = $(wildcard old_versions/*.sql)
 # @see http://www.postgresql.org/docs/current/static/extend-pgxs.html
 DATA =  $(NEW_EXTENSION_ARTIFACT) \
   $(OLD_VERSIONS) \
-  cdb_dataservices_server--0.7.2--0.7.3.sql \
-  cdb_dataservices_server--0.7.3--0.7.2.sql
+  cdb_dataservices_server--0.7.3--0.7.4.sql \
+  cdb_dataservices_server--0.7.4--0.7.3.sql
 
 REGRESS = $(notdir $(basename $(wildcard test/sql/*test.sql)))
 TEST_DIR = test/