update removal of ordered_merge as per comments

Author: tp

asv_bench/benchmarks/join_merge.py

@@ -1,6 +1,10 @@
 from .pandas_vb_common import *
 
-from pandas import merge_ordered
+try:
+    from pandas import merge_ordered
+except ImportError:
+    from pandas import ordered_merge as merge_ordered
+
 
 # ----------------------------------------------------------------------
 # Append

pandas/core/reshape/merge.py

@@ -1067,7 +1067,7 @@ def _get_join_indexers(left_keys, right_keys, sort=False, how='inner',
 
 
 class _OrderedMerge(_MergeOperation):
-    _merge_type = 'merge_ordered'
+    _merge_type = 'ordered_merge'
 
     def __init__(self, left, right, on=None, left_on=None, right_on=None,
                  left_index=False, right_index=False, axis=1,