[OXT-23] Fix license checksum for MIT licenses.

This was caused by d08f15bf88e5378b19bed88ce3e9bcc266c595a7 but went
unnoticed due to OXT-74.
[OXT-23] Fix license checksum for MIT licenses.

This was caused by d08f15bf88e5378b19bed88ce3e9bcc266c595a7 but went
unnoticed due to OXT-74.
[OXT-74] Delete insane class.

This is a duplicate of the class in the openembedded-core repo. The
only change we've made is reducing LIC_FILES_CHKSUM errors from ERROR
to WARNING.