libkmod-module: fix return code in error path

libkmod-module: fix return code in error path

ENOSYS is the wrong errno to return when we don't find a module in
kmod_module_insert_module(). Why is it there in the first place?  This
goes back to kmod v1 when we couldn't load modules by names, but we
should give a path instead.

708624a ("ELF: initial support for modinfo and strip of modversions and
vermagic.") changed that so we do a lazy-search by the module path in
this function. Later  f304afe ("Change error message to reflect
reality") fixed the log message but the return coded remained the same.