Raise proper exception when failing to deserialize an EC key

Continuation of 3d0f665

Signed-off-by: Ivan Kanakarakis <ivan.kanak@gmail.com>

Author: c00kiemon5ter

src/jwkest/jwk.py

@@ -602,7 +602,12 @@ def deserialize(self):
         except ValueError as err:
             raise DeSerializationNotPossible("%s" % err)
 
-        self.curve = NISTEllipticCurve.by_name(self.crv)
+        try:
+            self.curve = NISTEllipticCurve.by_name(self.crv)
+        except ECCException as err:
+            logger.warning(err)
+            raise DeSerializationNotPossible(err)
+
         if self.d:
             try:
                 if isinstance(self.d, six.string_types):