Always call through to super.onBackPressed in DialtactsActivity

moveTaskToBack is causing crashes in the Dialer when the back button is pressed.
This was legacy code that was unchanged in the new dialer. We should probably
just call through to super.onBackPressed regardless of whether or not the task
was at the top of the stack, to behave the same (navigation wise) as other apps.

Bug: 12015851
Change-Id: Ic0c3efb30b3874ad892b96a9fadd524313cfb782
(cherry picked from commit edf798aaf0eec1e94e1dc889f929a68c9c89922f)
diff --git a/src/com/android/dialer/DialtactsActivity.java b/src/com/android/dialer/DialtactsActivity.java
index 04934c7..1ab4601 100644
--- a/src/com/android/dialer/DialtactsActivity.java
+++ b/src/com/android/dialer/DialtactsActivity.java
@@ -887,12 +887,6 @@
         } else if (getInSearchUi()) {
             mSearchView.setText(null);
             mDialpadFragment.clearDialpad();
-        } else if (isTaskRoot()) {
-            // Instead of stopping, simply push this to the back of the stack.
-            // This is only done when running at the top of the stack;
-            // otherwise, we have been launched by someone else so need to
-            // allow the user to go back to the caller.
-            moveTaskToBack(false);
         } else {
             super.onBackPressed();
         }