[CORD-2696] Printing stacktrace for gRPC errors

Change-Id: I6a31a38ab5aa775b67d867a083e2491840e02dbb
(cherry picked from commit 59a785fc6d95a5d7f23334d8610344cc8f01eadd)
diff --git a/xos/coreapi/apihelper.py b/xos/coreapi/apihelper.py
index b353722..271e094 100644
--- a/xos/coreapi/apihelper.py
+++ b/xos/coreapi/apihelper.py
@@ -68,6 +68,11 @@
             return function(*args, **kwargs)
         except Exception as e:
 
+            import traceback
+            tb = traceback.format_exc()
+            print tb
+            # TODO can we propagate it over the APIs?
+
             if "context" in kwargs:
                 context = kwargs["context"]
             else: