extra logging for activity lifecycle

to help debug #2971
Closes #4342
// FREEBIE

src/org/thoughtcrime/securesms/ConversationActivity.java

@@ -208,6 +208,7 @@ public class ConversationActivity extends PassphraseRequiredActionBarActivity
 
   @Override
   protected void onCreate(Bundle state, @NonNull MasterSecret masterSecret) {
+    Log.w(TAG, "onCreate()");
     this.masterSecret = masterSecret;
 
     supportRequestWindowFeature(WindowCompat.FEATURE_ACTION_BAR_OVERLAY);