dev-manual: Updated checkout by branch

Example was incorrect. Fixed it.

(From yocto-docs rev: 7ae1c636e7a8c0448515f339476327bcaf21e63c)

Signed-off-by: Kristi Rifenbark <kristi.rifenbark@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

documentation/dev-manual/dev-manual-start.xml

@@ -398,8 +398,9 @@
                     For example, to access the files for the Yocto Project
                     2.3 Release (Pyro), use the following command:
                     <literallayout class='monospaced'>
-     $ git checkout -b origin/pyro
-     Switched to a new branch 'origin/pyro'
+     $ git checkout -b pyro origin/pyro
+     Branch pyro set up to track remote branch pyro from origin.
+     Switched to a new branch 'pyro'
                     </literallayout>
                     The previous command checks out the "pyro" branch and
                     reports that the branch is tracking the upstream
@@ -412,7 +413,7 @@
                     <literallayout class='monospaced'>
      $ git branch
        master
-     * origin/pyro
+     * pyro
                     </literallayout>
                     </para></listitem>
             </orderedlist>