from ?addprocs you see that calling addprocs(4)
addprocs(4) will add 4 processes on the local machine.
so the issue here is not a shared file system. all processes on your machine have access to the same, unique, file system, i.e. your disk. the only thing that changed to previous julia versions is that you need to push stuff onto the LOAD_PATH on all workers, as indeed @greg_plowman said.
If you had 2 machines, say, you would have to worry about this. either, you maintain exact equal code bases on both machines (via git probably), or you would have a file share between them, such that "/home/dfish/myFolder" is the exact same file on both of them, for example. on ubuntu this is not too bad to do yourself: SettingUpNFSHowTo - Community Help Wiki.