documentation/poky-ref-manual/extendpoky.xml: removed pokylinux.org link

There was a link whose URL was http://autobuilder.pokylinux.org:8010.
I changed the link to use yoctoproject.org.  Note that this URL
was not visible to the reader in the manual.  However, it was there
in the DocBook code.

(From yocto-docs rev: ca1cf9fb404f148fe4f0868630dc4f109231c5c3)

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

documentation/poky-ref-manual/extendpoky.xml

@@ -757,7 +757,7 @@ BBFILE_PRIORITY_emenlow = "6"
                 Experience shows that buildbot is a good fit for this role. 
                 What works well is to configure buildbot to make two types of builds:
                 incremental and full (from scratch).  
-                See <ulink url='http://autobuilder.pokylinux.org:8010'>poky autobuilder</ulink>
+                See <ulink url='http://autobuilder.yoctoproject.org:8010'>poky autobuilder</ulink>
                 for an example implementation that uses buildbot.
             </para>
             <para>