Fix bug when $nexus_root is set but $nexus_work_dir is not.
Add trailing directory
note why we recurse on $nexus_home_real.
add $nexus_work_dir_manage to determine whether or not the module should
manage the work directory.  In my infrastructure this directory is an
AWS EBS mount point and our volume management code handles this
directory resultung in a duplicate resource in our infrastructure..
Cahse one more spot for handling work_dir
Update to 1.3.1
Merge pull request #40 from hubspotdevops/fix_nexus_work_dir

Fix bug when $nexus_root is set but $nexus_work_dir is not.