Run(): don't include any default environment variables
Run(): don't include any default environment variables

When copying environment variables from the image's configuration to the
spec that we'll pass to the runtime, clear out any defaults that the
generate package might be supplying.  Currently, that's "$TERM".

Signed-off-by: Nalin Dahyabhai <nalin@redhat.com>

Closes: #820
Approved by: rhatdan

ipbabble/buildah,TomSweeneyRedHat/buildah,rhatdan/buildah,nalind/buildah-1,projectatomic/buildah,nalind/buildah-1,TomSweeneyRedHat/buildah,rhatdan/buildah,nalind/buildah,TomSweeneyRedHat/buildah,rhatdan/buildah,nalind/buildah-1,projectatomic/buildah,ipbabble/buildah,projectatomic/buildah,nalind/buildah