message: submodule: use symbolic names
  Same as what was recently done in memo.
diff: path = drake
  url = ../drake
  fetchRecurseSubmodules = false
  -[submodule "src/elle/json/modules/json-spirit"]
  +[submodule "json-spirit"]
  path = src/elle/json/modules/json-spirit
  url = https://github.com/infinitdotio/json-spirit
  fetchRecurseSubmodules = false
  -[submodule "src/elle/reactor/modules/miniupnp"]
  +[submodule "miniupnp"]
  path = src/elle/reactor/modules/miniupnp
  url = ../miniupnp
  fetchRecurseSubmodules = false
  -[submodule "src/elle/reactor/modules/libutp"]
  +[submodule "libutp"]
  path = src/elle/reactor/modules/libutp
  url = ../libutp
  fetchRecurseSubmodules = false
  -[submodule "src/elle/reactor/modules/osxfuse"]
  +[submodule "osxfuse"]
  path = src/elle/reactor/modules/osxfuse
  url = https://github.com/osxfuse/osxfuse
  fetchRecurseSubmodules = false
  -[submodule "src/elle/reactor/modules/dokany"]
  +[submodule "dokany"]
  path = src/elle/reactor/modules/dokany
  url = ../dokan
  fetchRecurseSubmodules = false
  -[submodule "src/elle/cryptography/modules/dopenssl"]
  +[submodule "dopenssl"]
  path = src/elle/cryptography/modules/dopenssl
  url = https://github.com/infinit/dopenssl
  fetchRecurseSubmodules = false
  