erp5testnode: downgrade version of erp5.util to 0.4.53

Finally, last change in erp5testnode is not needed, it was just required
to fix seleniumrunner software

software/erp5testnode/software.cfg

@@ -58,7 +58,7 @@ output = ${buildout:directory}/template-default.cfg
 mode = 0644
 
 [versions]
-erp5.util = 0.4.54
+erp5.util = 0.4.53
 slapos.recipe.template = 4.3
 dnspython = 1.15.0
 PyXML = 0.8.5