The default is not to email you a password if you know what the old one was.
In the control panel, on the Password tab under Users, just leave the dot in Change Your Password. Enter your old one, then your new one twice. Click the "Change, then email password" box. (Despite the wording on the submit button, it only does what you've told it to do by putting the dot beside the option you want.)
I just did this and even entered a wrong password just to make sure email doesn't go out. If you enter a wrong one, the error does let you know that a password can be emailed, but you have to request that option.