[yocto] Yocto Development Manual Appendix B redux

[jfabernathy]

Just to simplify the previous thread on this subject.

To solve the issue I brought up about the Development Manual Appendix B 
examples, it boils down to this:

1.  A denzil branch of poky-extra has now been created to solve the bug 
I experienced.
2.  The only instruction that needs to be added to the appendix is to 
have the user checkout the denzil branch of poky-extra to match the fact 
that they are using the denzil branch of poky.
3.  The warning about a kernel parameter mismatch should be ignored.  A 
note to this effect would be helpful.

With the 3 items taken into account, the examples run as documented 
either doing B.1, then B.2 or just starting with B.2.

Jim A