ref-manual, mega-manual: Updated figure for source fetching

Fixes [YOCTO #2808]

The Build Directory should be inside the BB blue box here and
not outside of it.  Adjusted the figure, which resides in
the figures directory of both the ref-manual and the
mega-manual.  Also had to widen the image footprint to make
it readable.

(From yocto-docs rev: b4ff9292cf629894fda6ad4a29fbdaad85f43cd0)

Signed-off-by: Scott Rifenbark <scott.m.rifenbark@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/ref-manual/closer-look.xml

@@ -618,7 +618,7 @@
             <para>
                 The first stages of building a recipe are to fetch and unpack
                 the source code:
-                <imagedata fileref="figures/source-fetching.png" align="center" width="6.5in" depth="4in" />
+                <imagedata fileref="figures/source-fetching.png" align="center" width="6.5in" depth="5in" />
             </para>
 
             <para>