fix(db_ops): fix two incorrectly named variables

Author: kvwalker

lib/operations/db_ops.js

@@ -336,8 +336,8 @@ function createListener(db, e, object) {
  * @param {Object} [options] Optional settings. See Db.prototype.dropCollection for a list of options.
  * @param {Db~resultCallback} [callback] The results callback
  */
-function dropCollection(db, cmd, options, callback) {
-  executeCommand(db, cmd, options, (err, result) => {
+function dropCollection(db, name, options, callback) {
+  executeCommand(db, name, options, (err, result) => {
     // Did the user destroy the topology
     if (db.serverConfig && db.serverConfig.isDestroyed()) {
       return callback(new MongoError('topology was destroyed'));
@@ -505,8 +505,8 @@ function executeCommand(db, command, options, callback) {
  * @param {object} [options] Optional settings. See Db.prototype.executeDbAdminCommand for a list of options.
  * @param {Db~resultCallback} [callback] The command result callback
  */
-function executeDbAdminCommand(db, selector, options, callback) {
-  db.s.topology.command('admin.$cmd', selector, options, (err, result) => {
+function executeDbAdminCommand(db, command, options, callback) {
+  db.s.topology.command('admin.$cmd', command, options, (err, result) => {
     // Did the user destroy the topology
     if (db.serverConfig && db.serverConfig.isDestroyed()) {
       return callback(new MongoError('topology was destroyed'));