Fix t09_repo:IncludeRepo3Test failing

The output of the template parser seems to have changed with go 1.20

system/t09_repo/IncludeRepo3Test_gold

@@ -1 +1 @@
-ERROR: error parsing -repo template: template: repo:1: unexpected "}" in operand; missing space?
+ERROR: error parsing -repo template: template: repo:1: bad character U+007D '}'

system/t09_repo/include.py

@@ -1,8 +1,9 @@
-import tempfile
-import shutil
-import os
 import inspect
+import os
 import re
+import shutil
+import tempfile
+
 from lib import BaseTest
 
 
@@ -68,9 +69,6 @@ class IncludeRepo3Test(BaseTest):
     runCmd = "aptly repo include -no-remove-files -keyring=${files}/aptly.pub -repo=my-{{.Distribution} ${changes}"
     expectedCode = 1
 
-    def outputMatchPrepare(_, s):
-        return s.replace('; missing space?', '')
-
 
 class IncludeRepo4Test(BaseTest):
     """