update the deferred loader
work around locate-library issue

locate-library incorrectly generates a set of suffixes to extend the
base library name (".elc" ".elc.gz" ".el" ".el.gz" "" ".gz"), while it
should be just (".elc" ".elc.gz" ".el" ".el.gz") when nosuffix is
nil. This leads to spurious paths found, like name.gz. This needs to
be worked around til this is fixed in emacs.