Added support for -size option. Most of the changes are in mkextrafs script to provide lvm volume of required size to host the dm disk.
Added support for -size option. Most of the changes are in
mkextrafs script to provide lvm volume of required size to
host the dm disk.

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