Singularity image path issue when built from docker image

[Ajburdett]

Built docker image from dockerfile - built singularity from docker daemon. When executing the docker image it works, when trying to use the singularity image it couldn't find hairpin2 on path. Possible cause - discrepancies with user handling between docker and singularity.

All works fine if singularity image is built directly from Singularity.def