Sumo refresh

Update external subtrees to latest Yocto sumo.

Change-Id: I8364f32bef079841c6e57f1c587f4b1bedf62fef
Signed-off-by: Brad Bishop <bradleyb@fuzziesquirrel.com>
diff --git a/poky/documentation/ref-manual/ref-manual.xml b/poky/documentation/ref-manual/ref-manual.xml
index 169a31e..82c1d0b 100644
--- a/poky/documentation/ref-manual/ref-manual.xml
+++ b/poky/documentation/ref-manual/ref-manual.xml
@@ -122,6 +122,11 @@
                 <date>May 2018</date>
                 <revremark>Released with the Yocto Project 2.5 Release.</revremark>
             </revision>
+            <revision>
+                <revnumber>2.5.1</revnumber>
+                <date>September 2018</date>
+                <revremark>The initial document released with the Yocto Project 2.5.1 Release.</revremark>
+            </revision>
         </revhistory>
 
     <copyright>