Make systemd swap hack run on Ubuntu 15.
So, the scripts are now in clientside/tmcc/linux since they're the same for any systemd-based Linux, and the centos7 and ubuntu15 makefiles install those files. Also had to improve fixup-fstab-swaps to handle the case where the / is something like /dev/disk/by-uuid/<UUID> which is a symlink to the real dev. So try readlink -f to handle that.
clientside/tmcc/centos7/emulab-fstab-fixup.service → clientside/tmcc/linux/emulab-fstab-fixup.service