if you run Autostarts, you can see that under 'New Outgoing Call' there is an entry by Dialer. Clicking on that and you can see that the intent is handled by com.android.phone.ProcessOutgoingCallTest, which is exactly the code I found above. From here, you can just choose 'Disable' and autostarts will remove the intent, and you'll have your 7 digit phone numbers back without the 617 area code. Note that I had to restart the Dialer for this change to work (or, rather, it crashed out from under me when I changed it). Though, there are no ill effects.