Fix the XOS documentation

Change-Id: Ia633c5a0089d8cd095af102fa1bd0ec084973231
diff --git a/docs/Makefile b/docs/Makefile
index 0cd84bd..86248c0 100644
--- a/docs/Makefile
+++ b/docs/Makefile
@@ -10,7 +10,7 @@
 # use bash for pushd/popd, and to fail if commands within  a pipe fail
 SHELL = bash -o pipefail
 
-GENERATED_DOCS = 
+GENERATED_DOCS =
 
 LINT_STYLE ?= mdl_relaxed.rb