codeconverter: script for automating QOM code cleanups

codeconverter: script for automating QOM code cleanups

This started as a simple script that scanned for regular
expressions, but became more and more complex when exceptions to
the rules were found.

I don't know if this should be maintained in the QEMU source tree
long term (maybe it can be reused for other code transformations
that Coccinelle can't handle).  In either case, this is included
as part of the patch series to document how exactly the automated
code transformations in the next patches were done.

Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>
Message-Id: <20200831210740.126168-7-ehabkost@redhat.com>
Signed-off-by: Eduardo Habkost <ehabkost@redhat.com>