Update browseable for MessagingService.

1. layout fixes
2. name changes in sample. (redo of ag/586904 which was lost from lmp-docs)

Change-Id: I3a2afafb5b878ba90b8ae6314220af19b3dfbb09

samples/browseable/MessagingService/res/layout-land/fragment_message_me.xml

@@ -61,7 +61,6 @@
             android:layout_above="@id/clear"
             android:layout_width="match_parent"
             android:layout_height="match_parent"
-            android:maxLines="20"
             android:scrollbars="vertical"/>
     </RelativeLayout>
 </LinearLayout>

samples/browseable/MessagingService/res/layout/fragment_message_me.xml

@@ -47,7 +47,6 @@
         android:layout_width="match_parent"
         android:layout_height="0dp"
         android:layout_weight="1"
-        android:maxLines="20"
         android:scrollbars="vertical"/>
     <Button
         android:layout_width="match_parent"

samples/browseable/MessagingService/src/com.example.android.messagingservice/Conversations.java

@@ -45,10 +45,10 @@ public class Conversations {
      * Senders of the said messages.
      */
     private static final String[] PARTICIPANTS = new String[]{
-            "John Rambo",
-            "Han Solo",
-            "Rocky Balboa",
-            "Lara Croft"
+            "John Smith",
+            "Robert Lawrence",
+            "James Smith",
+            "Jane Doe"
     };
 
     static class Conversation {