GATK4: fix login issue with Spark and Docker
GATK4: fix login issue with Spark and Docker

Docker containers get run as an external user ID which might not
be present in the internal container /etc/passwd, causing login
errors when running Spark. This checks for this case and allows
adding the user to avoid the issue.

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