message: removed libevent module
diff: path = leveldb
  url = https://github.com/bitcoin-core/leveldb
  branch = 64052c76c567cff3dad32d1db0ef969d97b5882f
  -[submodule "libevent"]
  - path = libevent
  - url = https://github.com/libevent/libevent
  - branch = c51b159cff9f5e86696f5b9a4c6f517276056258
  