[yocto] [yocto-docs][PATCH 3/5] ref-manual: add preamble to buildhistory section on top-level contents

[Paul Eggleton]

Add a paragraph to the top of the section on buildhistory mentioning the
metadata-revs file and the top-level directories.

Signed-off-by: Paul Eggleton <paul.eggleton at linux.intel.com>
---
 documentation/ref-manual/usingpoky.xml |    8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/documentation/ref-manual/usingpoky.xml b/documentation/ref-manual/usingpoky.xml
index 101411c..25a2259 100644
--- a/documentation/ref-manual/usingpoky.xml
+++ b/documentation/ref-manual/usingpoky.xml
@@ -503,6 +503,14 @@
             <imagedata fileref="figures/buildhistory.png" align="center" width="6in" depth="4in" />
         </para>
 
+        <para>At the top level, there is a <filename>metadata-revs</filename> file
+            listing the revisions of the repositories for the layers enabled
+            when the build was produced. The rest of the data is split into separate
+            <filename>packages</filename>, <filename>images</filename> and
+            <filename>sdk</filename> directories, the contents of which are
+            described below.
+        </para>
+
         <section id='build-history-package-information'>
             <title>Build History Package Information</title>
 
-- 
1.7.10.4