Run fails if Aragorn predicts unreliable anticodons

[satta]

Aragorn may produce output of the form:

    tRNA-???(.ga)
    81 bases, %GC = 55.6
    Sequence [858164,858244]

This will cause the output parser to fail, terminating the run:

Error executing process > 'predict_tRNA (1)'

Caused by:
  Process 'predict_tRNA (1)' terminated with an error exit status

Command executed:

  aragorn -t pseudo.pseudochr.fasta > out
  grep -E -C2 '(nucleotides|Sequence)' out > 1
  aragorn_to_gff3.lua < 1 > 2
  gt gff3 -sort -tidy -retainids 2 > aragorn.gff3

Command exit status:
  1

Command output:
  (empty)

Command error:
  gt: error: could not execute script ...fs/users/nfs_s/ss34/annot-nf/bin/aragorn_to_gff3.lua:59: attempt to concatenate global 'anticodon' (a nil value)