Fix Salmon memoization.
Fix Salmon memoization.

Also drop using --useVBOpt until the next version is out, it
can cause segfaults.

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