Backport of Bug#26930148 POOR RESOURCE MANAGEMENT IN NDB COMMAND LINE PROGRAMS
ndb_load_defaults() lack matching call to ndb_free_defaults(), in trunk this
was fixed by introducing Ndb_opts instead of ndb_load_defaults. In 7.6 we
need to add calls to ndb_free_defaults().

Change-Id: I3d93c646c52518b17ae6d5456b3a0bffda204b6d