Move the script locking code that Rob did a long time ago (the stuff that is at the start of scripts like exports_setup) into a library function. I'm tired of duplicating it!
Move the script locking code that Rob did a long time ago (the stuff
that is at the start of scripts like exports_setup) into a library
function. I'm tired of duplicating it!

nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome,nmc-probe/emulab-nome