manifest: Unstage 15.1

Change-Id: Ib3d3ac1b2e54cc8acf41cb7f490db3f606a8e528
diff --git a/README.mkdn b/README.mkdn
index 9470319..fdb5719 100644
--- a/README.mkdn
+++ b/README.mkdn
@@ -33,7 +33,7 @@
 
 To initialize your local repository using the LineageOS trees, use a command like this:
 
-    repo init -u git://github.com/LineageOS/android.git -b staging/lineage-15.1
+    repo init -u git://github.com/LineageOS/android.git -b lineage-15.1
 
 Then to sync up: