Fix InternalException on api

Author: jadsonmonteiro

pyslicer/api.py

@@ -128,8 +128,8 @@ def _handler_request(self, req):
 
         try:
             result = ujson.loads(req.text)
-        except ValueError:
-            raise exceptions.InternalException
+        except ValueError as e:
+            raise exceptions.InternalException("Error while trying to load Json: %s" % e.message)
 
         sd_response = SDHandlerResponse(
             result=result,