bitbake: buildinfohelper: work around unicode exceptions

bitbake: buildinfohelper: work around unicode exceptions

We have been seeing UnicodeDecodeErrors when handling the
ImagePkgList MetadataEvent in ORMWrapper's
save_target_file_information() if the event includes filenames
that include non-ASCII characters.

In the short term work around this by converting paths to the
unicode type when passing them to Django's ORM. This is a bit of
a hack but it's too late in the cycle to do anything more invasive.

[YOCTO #9142]

(Bitbake rev: f50fff03b3de02e73a3cc2eb9935f7c345dbddc4)

Signed-off-by: Joshua Lock <joshua.g.lock@intel.com>
Signed-off-by: Elliot Smith <elliot.smith@intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>