Merge pull request #23 from mk-fg/collectd_converter_null_name_fix

Handle None returned from collectd metric name converter correctly

bucky/collectd.py

@@ -243,9 +243,10 @@ def convert(self, sample):
         default = self.converters["_default"]
         handler = self.converters.get(sample["plugin"], default)
         try:
-            name = '.'.join(handler(sample))
-            if name is None:
+            name_parts = handler(sample)
+            if name_parts is None:
                 return  # treat None as "ignore sample"
+            name = '.'.join(name_parts)
         except:
             log.exception("Exception in sample handler  %s (%s):", sample["plugin"], handler)
             return