L2SS-544: Be more specific when matching exceptions

tangostationcontrol/tangostationcontrol/toolkit/archiver.py

@@ -208,11 +208,11 @@ class Archiver():
             self.cm.write_attribute('SetPeriodEvent', event_period)
             self.cm.AttributeAdd()
             logger.info(f"Attribute {attribute_name} added to archiving list!")
-        except Exception as e:
-            if 'already archived' not in str(e).lower():
-                raise Exception from e
-            else:
+        except DevFailed as e:
+            if e.args[0].reason == 'Already archived':
                 logger.warning(f"Attribute {attribute_name} already in archiving list!")
+            else:
+                raise
 
     def add_attributes_by_device(self,device_name,global_archive_period:int = None, es_name:str=None, exclude:list = []):
         """