AWS: ensure GTF information in place for STAR
AWS: ensure GTF information in place for STAR

Building STAR indices requires knowing about genome resources GTF
files, which aren't yet in place when starting. Thanks to Gabriel
Valbuena.

lbeltrame/bcbio-nextgen,chapmanb/bcbio-nextgen,a113n/bcbio-nextgen,biocyberman/bcbio-nextgen,lbeltrame/bcbio-nextgen,biocyberman/bcbio-nextgen,mjafin/bcbio-nextgen,chapmanb/bcbio-nextgen,brainstorm/bcbio-nextgen,vladsaveliev/bcbio-nextgen,lbeltrame/bcbio-nextgen,vladsaveliev/bcbio-nextgen,biocyberman/bcbio-nextgen,brainstorm/bcbio-nextgen,chapmanb/bcbio-nextgen,mjafin/bcbio-nextgen,brainstorm/bcbio-nextgen,a113n/bcbio-nextgen,a113n/bcbio-nextgen,mjafin/bcbio-nextgen,vladsaveliev/bcbio-nextgen