Change hard numeric support link with smartlink

BUG=639537
TEST=Logged onto a managed account, open SysTray menu, click on
"This device is managed by ..." item.  This should briefly open
  https://support.google.com/chromebook/?p=managed
which will quickly redirect to something like
  https://support.google.com/chromebook/answer/2535613?p=managed&rd=1

Review-Url: https://codereview.chromium.org/2308613002
Cr-Commit-Position: refs/heads/master@{#417024}

chrome/common/url_constants.cc

@@ -581,7 +581,7 @@ const char kNaturalScrollHelpURL[] =
 
 #if defined(OS_CHROMEOS)
 const char kLearnMoreEnterpriseURL[] =
-    "https://support.google.com/chromebook/answer/2535613";
+    "https://support.google.com/chromebook/?p=managed";
 #endif
 
 const char kRemoveNonCWSExtensionURL[] =