Fix cryptographic usage mask handling for CreateKeyPair

This change fixes how the ProxyKmipClient handles cryptographic
usage mask values for the CreateKeyPair operation. Originally,
both Encrypt and Decrypt were set by default for both public and
private keys. This is incorrect behavior for certain algorithms.
Now, only the masks specified by the caller are set on the key
pair.

Fixes #412

kmip/core/objects.py

@@ -2453,6 +2453,8 @@ class TemplateAttribute(Struct):
             if len(self.attributes) != len(other.attributes):
                 return False
 
+            # TODO (peter-hamilton) Allow order independence?
+
             for i in xrange(len(self.names)):
                 a = self.names[i]
                 b = other.names[i]