remove unused cimport (#21619)

jbrockmendel · jreback · commit 4922c0e0ab70 · 2018-06-25T06:56:55.000-04:00
diff --git a/pandas/_libs/hashtable_class_helper.pxi.in b/pandas/_libs/hashtable_class_helper.pxi.in
@@ -4,8 +4,6 @@ Template for each `dtype` helper function for hashtable
 WARNING: DO NOT edit .pxi FILE directly, .pxi is generated from .pxi.in
 """
 
-from missing cimport is_null_datetimelike
-
 
 #----------------------------------------------------------------------
 # VectorData
