Revert "Do nothing in case if log rotation is not enabled."

This reverts commit 4d67c5a4.

It is not safe to have fallback in administration, and log rotation is
always nice feature.

slapos/recipe/erp5/src/slapos/recipe/erp5/__init__.py

@@ -146,15 +146,11 @@ class Recipe(BaseSlapRecipe):
 
   def registerLogRotation(self, name, log_file_list, postrotate_script):
     """Register new log rotation requirement"""
-    if getattr(self, 'logrotate_d', None) is not None:
-      open(os.path.join(self.logrotate_d, name), 'w').write(
+    open(os.path.join(self.logrotate_d, name), 'w').write(
         self.substituteTemplate(self.getTemplateFilename(
           'logrotate_entry.in'),
           dict(file_list=' '.join(['"'+q+'"' for q in log_file_list]),
             postrotate=postrotate_script, olddir=self.logrotate_backup)))
-    else:
-      self.logger.warning('No log rotation configured for %r, as log rotate '
-          'is not configured' % name)
 
   def linkBinary(self):
     """Links binaries to instance's bin directory for easier exposal"""