Don't call executePendingTransactions().

Not doing so no longer crashes on when handling notifications, and is
causing runtime exceptions from the OS when board opening chat causes
it to be called recursively.

xwords4/android/XWords4/src/org/eehouse/android/xw4/MainActivity.java

@@ -371,6 +371,10 @@ public class MainActivity extends XWActivity
             .add( id, fragment )
             .addToBackStack( newName )
             .commit();
-        fm.executePendingTransactions();
+        // Don't do this. It causes an exception if e.g. from fragment.start()
+        // I wind up launching another fragment and calling into this code
+        // again. If I need executePendingTransactions() I'm doing something
+        // else wrong.
+        // fm.executePendingTransactions();
     }
 }