Disabling Google Voice Dialer
Okay, I figured out how to set the good ol' Voice Commands app as the default voice commands interface.  It has to be done while not connected to a hands free device via Bluetooth.


Tap into the Phone app
Tap the Phone app's microphone icon


In my case a prompt appeared asking me to select the default app to handle voice commands.  Thereafter, it's used the correct Voice Commands app when connected via Bluetooth.



For those who wanted to know how to disable Google Now, here's how it's done:


Swipe up from the Home icon to activate Google Now
Scroll all the way to the bottom
Tap the Overflow menu (three vertical dot icon)
Tap Settings
Tap Google Now
Tap the OFF/ON switch in the upper-right to disable Google Now