Make constructor public to handle resume/rotate

Change-Id: I4953ae6ed753792eb8a7aced99474fe09976f140
diff --git a/src/com/android/mail/ui/ConversationViewFragment.java b/src/com/android/mail/ui/ConversationViewFragment.java
index d3b19bc..e885a7c 100644
--- a/src/com/android/mail/ui/ConversationViewFragment.java
+++ b/src/com/android/mail/ui/ConversationViewFragment.java
@@ -86,7 +86,11 @@
     private static final String ARG_ACCOUNT = "account";
     private static final String ARG_CONVERSATION = "conversation";
 
+    /**
+     * Constructor needs to be public to handle orientation changes and activity lifecycle events.
+     */
     public ConversationViewFragment() {
+        super();
     }
 
     /**