bitbake: data_smart: fix resetting of reference on variablehistory

There is no "datasmart" member, only dataroot. This dates back to the
original implementation of variable history support - it's surprising we
haven't noticed the issue until now, but I guess it's rare to change a
copy of a datastore in a manner which using the old reference would
cause an issue.

(Bitbake rev: febd5534b07edfdef15cedb0578730c582c7373f)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/data_smart.py

@@ -844,7 +844,7 @@ class DataSmart(MutableMapping):
         data = DataSmart()
         data.dict["_data"] = self.dict
         data.varhistory = self.varhistory.copy()
-        data.varhistory.datasmart = data
+        data.varhistory.dataroot = data
         data.inchistory = self.inchistory.copy()
 
         data._tracking = self._tracking