trim the front of variables. Error if there are other spaces present.
Leave the value alone.
Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)
match dock functionality, and not try to achieve shell-sourcing compatibility
Docker-DCO-1.1-Signed-off-by: Vincent Batts <vbatts@redhat.com> (github: vbatts)