Fix crash in classic_parse(): Fix condition for freeing the jet table
Fix crash in classic_parse(): Fix condition for freeing the jet table

The only case in which it should be retained (for optional later
rebuild) is if we are in the first stage of a one-step-parse (in this
first stage, a parse with null_count=0 is requested and
opt->max_null_count > 0).

linas/link-grammar,linas/link-grammar,opencog/link-grammar,ampli/link-grammar,opencog/link-grammar,opencog/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,linas/link-grammar,opencog/link-grammar,opencog/link-grammar,linas/link-grammar,ampli/link-grammar,ampli/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,linas/link-grammar,ampli/link-grammar,opencog/link-grammar,opencog/link-grammar,linas/link-grammar,opencog/link-grammar,ampli/link-grammar,linas/link-grammar,opencog/link-grammar