GEMINI: skip database creation of MuTect2
GEMINI: skip database creation of MuTect2

MuTect2 output contains non-diploid calls for multiallelic low
frequency calls. These cause database creation to fail so we skip
for now, but do create annotated VCFs with vcfanno for direct use.
Fixes #2231

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