Enabled cloning of submodules in migrations test
Enabled cloning of submodules in migrations test

- we start Ghost in this test but Ghost will check Casper, which isn't
  cloned without this commit

janvt/Ghost,ErisDS/Ghost,bitjson/Ghost,ErisDS/Ghost,TryGhost/Ghost,TryGhost/Ghost,janvt/Ghost,e10/Ghost,ErisDS/Ghost,bitjson/Ghost,TryGhost/Ghost,e10/Ghost