Fix chipseq resource logic when peak calling is not requested.
Fix chipseq resource logic when peak calling is not requested.

Thanks to @mistrm82 for reporting and testing.

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