Deprecate NNVM warning msg

yzhliu · yzhliu · commit 39d3e2e8234d · 2019-11-14T13:07:35.000-08:00
diff --git a/nnvm/python/nnvm/__init__.py b/nnvm/python/nnvm/__init__.py
@@ -10,3 +10,7 @@
 from . import frontend
 
 __version__ = _base.__version__
+
+import warnings
+warnings.warn("NNVM is deprecated and will be removed in a future version. Use Relay instead.",
+              FutureWarning)
