1) AUH was never adapted to newer testimage, which a) requires 'ptest' in TEST_SUITES if ptests are to be run; b) writes logs to ptest_log/* instead of ptest.log. 2) finding logs for a certain machine is doubly broken: for qemux86 machine it returns qemux86_64 logs, for qemux86-64 machine it returns nothing at all because logs are in qemux86_64 (underscore!) directory.
Patches posted to yocto@ list and available here: http://git.yoctoproject.org/cgit/cgit.cgi/auto-upgrade-helper/log/?h=devel