Revert "bb.fatal: Raise a BBHandledException instead of exiting"

Sanity test failures are no longer fatal with this change so whilst
its the right idea, the code paths need more work.

This reverts commit a50017ba71250e1710a6425b60ac7e3f03d88295.
usermanual.xml: Two new sections added to BitBake "Description"

1. Added a new section "Appending and Prepending (override style
   syntax)".  This section shows how the append and prepend operators
   work using the override style syntax.

2. Added a new section "Removing (override style syntax)".  This
   section describes the new "_remove" operator.

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

The syntax used for checkPackages implies a copy is returned but it
did not do so. Make it so.

This is fixes universe builds where error messaages were being shown
but there should have only been warnings.

[YOCTO #5222]

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>
data_smart: Fix variable reference issues

The change to use the expansion cache in VariableParse was incorrect as
it was adding in references it shouldn't have been. This patch corrects
the codepaths and ensures the references are correct.

The cache version is bumped since the previous bug could have leave
to invalid checksum calculations and a clean cache is therefore desireable.

The impact of the bug was that sstate was not getting reused when it should
and some tasks were also being rerun when they should not have been.

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