Logically revert "Directly show the layout selection screen."

This is logical revert of a CL [1] that was recently re-introduced as
part of my recent CL [2].

Reason for revert:
Directly showing the layout selection screen when there is no hardware
keyboard is selected yet is not something people had been familiar
with.

That behavior had been enabled only in a short period during Android N
development cycle and was never enabled in most of production builds.
To avoid confusions, let's revert back to the true Android M behavior
by logically reverting that change.

 [1]: I4483dfc89afc8d148b2cfa7c6a5f66d2a02f712a
      17b6319884
 [2]: I7a2ed6dd39dcd8207d3d94e12cd01d5d67ba4bb5
      7129b374bb

Change-Id: If0529e20cbff432d38d9b2dd74eeb3af0da5baf1
Bug: 66498367
Fix: 75318417
Test: Manually verified

src/com/android/settings/inputmethod/PhysicalKeyboardFragment.java

@@ -187,13 +187,10 @@ public final class PhysicalKeyboardFragment extends SettingsPreferenceFragment
     }
 
     private void showKeyboardLayoutDialog(InputDeviceIdentifier inputDeviceIdentifier) {
-        KeyboardLayoutDialogFragment fragment = (KeyboardLayoutDialogFragment)
-                getFragmentManager().findFragmentByTag("keyboardLayout");
-        if (fragment == null) {
-            fragment = new KeyboardLayoutDialogFragment(inputDeviceIdentifier);
-            fragment.setTargetFragment(this, 0);
-            fragment.show(getActivity().getFragmentManager(), "keyboardLayout");
-        }
+        KeyboardLayoutDialogFragment fragment = new KeyboardLayoutDialogFragment(
+                inputDeviceIdentifier);
+        fragment.setTargetFragment(this, 0);
+        fragment.show(getActivity().getFragmentManager(), "keyboardLayout");
     }
 
     private void registerShowVirtualKeyboardSettingsObserver() {