AU: Restrict URL/version change over D-Bus to non-official builds only.

BUG=7159
TEST=unit tests, test on device

Change-Id: I7dd6293d3e61db123b2be2f1e3ee283fcb5ba968

Review URL: http://codereview.chromium.org/3965001
diff --git a/utils.h b/utils.h
index 9beae04..57fb3bb 100644
--- a/utils.h
+++ b/utils.h
@@ -21,10 +21,7 @@
 
 namespace utils {
 
-// Returns true if this is an official Chrome OS build, false
-// otherwise. Currently, this routine errs on the official build side
-// -- if it doesn't recognize the update track as non-official, it
-// assumes the build is official.
+// Returns true if this is an official Chrome OS build, false otherwise.
 bool IsOfficialBuild();
 
 // Returns true if the OOBE process has been completed and EULA accepted, false