minor: use dropIndexes instead of delete

pymongo/collection.py

@@ -673,7 +673,7 @@ class Collection(object):
 
         self.__database.connection._purge_index(self.__database.name,
                                                 self.__name, name)
-        self.__database.command("deleteIndexes", self.__name, index=name,
+        self.__database.command("dropIndexes", self.__name, index=name,
                                 allowable_errors=["ns not found"])
 
     def index_information(self):

pymongo/dbref.py

@@ -75,7 +75,7 @@ class DBRef(object):
         Generally not needed by application developers
         """
         doc = SON([("$ref", self.collection),
-                         ("$id", self.id)])
+                   ("$id", self.id)])
         if self.database is not None:
             doc["$db"] = self.database
         return doc