Functions defined in outer scope don't propogate.

export -f may be used on a function to make sure that it is
passed to the subshell.

Change-Id: Ic9562e0426248f2db9b5ad33855e0ec6995688f1
Reviewed-on: https://review.openstack.org/33529
Reviewed-by: Clark Boylan <clark.boylan@gmail.com>
Approved: Jeremy Stanley <fungi@yuggoth.org>
Reviewed-by: Jeremy Stanley <fungi@yuggoth.org>
Tested-by: Jenkins