base/utility-tasks.bbclass: Drop do_setscene and do_rebuild
The do_setscene task only exists for rebuild support now as all its other
functionality has been superceeded. The rebuild task currently crashes due
to removal of the working directory and therefore isn't working for anyone.
It also interacts extremely badly with the newer sstate technology to the
point of being dangerous.
Summary, if we want rebuild support it needs a reimplementation so remove
this version and all its remnants and hacks.
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
