bitbake-layers: fix show-appends and flatten for recent cooker changes

Fixes the show-appends and flatten subcommands for recent refactoring in
cooker.

[YOCTO #4536]
[YOCTO #4535]

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
build: Avoid empty promises

The "see xxx for further information" is misleading since it is just
the same information. Clarify just to mention the that this is the location
of the logfile without any empty promise.

[YOCTO #4343]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
cooker/cookerdata: Fix up event handling for hob

The init function call was clobbering data hob relies on injecting, fix
this so the data injected by hob isn't overwritten.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
server: Remove none server

The process server backend has been serving well as the default for a long
time now and the UI model is much better thought out that it used to be. With
the move to make bitbake a memory resident process, the none server is now
looking rather pointless and complicates the code needlessly. Lets therefore
now remove it.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
server/bitbake: Remove launchUI method

With the removal of the none server type, we can remove the launchUI
method and simplify the code slightly.

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>