Fix for 0 showing up when longpressed in emergency dialer
Fix for 0 showing up when longpressed in emergency dialer

Add the same logic in Dialer that erases the previous digit into
Emergency Dialer. Also remove some unneeded legacy code.

Bug: 18102844
Change-Id: If46cf7d44f9f25c58cfc395bded4788233e245c2

md5555/android_packages_services_Telephony