Source functions in rejoin-stack.sh

stackrc loads localrc and localrc can use functions
like enable_service and disable_service. Make sure
the functions are defined before loading stackrc.

Change-Id: Ied7bbe0d228f252902cc491b8db0738c5071f06b
Signed-off-by: Doug Hellmann <doug.hellmann@dreamhost.com>
Merge "Source functions in rejoin-stack.sh"