Avoid using the 'sample' syntax to refer to Phone Application, in the core.

This adds a build dependency on the PhoneApp, and the core build fails on
configurations that do not have Phone Application.

Build Error:
frameworks/base/core/java/android/widget/TwoLineListItem.java:31: error 2: Error reading file for include "" packages/apps/Phone/res/layout/dialer_list_item.xml