Speed up DictAttribute setting slightly.

Author: dan-blanchard

drmaa/helpers.py

@@ -198,8 +198,7 @@ def __init__(self, name):
         self.name = name
 
     def __set__(self, instance, value):
-        v = ["{0}={1}".format(k, v) for (k, v) in value.items()]
-        v = [el.encode() if not isinstance(el, bytes) else el for el in v]
+        v = ["{0}={1}".format(k, v).encode() for (k, v) in value.items()]
         c(drmaa_set_vector_attribute, instance, self.name,
           string_vector(v))