The default port of 5555 was removed a while back, but the help text was
never updated, and other contexts still allow a default port.
Bug: https://issuetracker.google.com/128561172
Test: manual
Change-Id: I6e5e6edeb2243386a0301c0a6cad569189f9910e
This will make it easier to add new types of transports by combining the
logic the adb server and adb daemon use to connect to things.
Bug:121166534
Test: adb connect against a cuttlefish instance over the shm proxy.
Change-Id: Ic7fc848c60a85eef968c3735838c87cb7fdaf38b