battenberg: ensure local R used for runs
battenberg: ensure local R used for runs

Fixes issues with resolving Rscript. Thanks to @ohofmann

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