take --variant-input even in targets with no reads
take --variant-input even in targets with no reads

Bug: you are missing the last variant in your target region.  If you run on a
single region with no reads you get no typing information for your VCF.

This commit resolves this issue.

Also, added better error handling, which prints that the message came from
freebayes.

godotgildor/freebayes,godotgildor/freebayes,ekg/freebayes,gkno/freebayes,godotgildor/freebayes,gkno/freebayes,godotgildor/freebayes,ekg/freebayes,godotgildor/freebayes,nh13/freebayes,ekg/freebayes,nh13/freebayes,nh13/freebayes,gkno/freebayes,gkno/freebayes,ekg/freebayes,nh13/freebayes,ekg/freebayes,gkno/freebayes,nh13/freebayes