Avoid gsutil failures for DeepVariant on Google Compute instances
Avoid gsutil failures for DeepVariant on Google Compute instances

gsutil from conda packages can fail when global /etc/boto.cfg files
are present, like on Google Compute:

https://github.com/GoogleCloudPlatform/gsutil/issues/516

This works around the issue by ignoring this file during install. Fixes
chapmanb/bcbio-nextgen#2613

chapmanb/cloudbiolinux,chapmanb/cloudbiolinux,chapmanb/cloudbiolinux,chapmanb/cloudbiolinux