NODE-954 Remove write concern from reindex helper as it will not be supported in 3.6

Author: christkv

lib/collection.js

@@ -1788,9 +1788,6 @@ var reIndex = function(self, options, callback) {
   // Reindex
   var cmd = {'reIndex':self.s.name};
 
-  // Decorate command with writeConcern if supported
-  decorateWithWriteConcern(cmd, self, options);
-
   // Execute the command
   self.s.db.command(cmd, options, function(err, result) {
     if(callback == null) return;