- Make storage/ndb autodetect if include/my_default.h exists and thus need to link
   with new mysys_ssl library
 - Add minimal wrapper around load_defults in ndb_getopt to avoid exposing my_default.h
   "everywhere", two exceptions confirm the rule since those are hardcore users
 - Rename ndb_opts.c to ndb_opt.cpp and mark public functions therein as "extern C"