Review 22068

Russell C. Jackson (Rusty)
Pull the configuration items out into mkdirs.cfg and source that file
in mkdirs.sh. Makes it a little cleaner, and less likely for someone
to mess up the mkdirs.sh script. Also preps for potential future
configure_sdp.sh script to ask questions and create the mkdirs.cfg file.
Tip: Use n and p to cycle through the changes.