PipeReader: support plain fd without file obj
ebuild-ipc: use PipeReader in _wait
ebuild-ipc: use PipeReader in _receive_reply
ebuild-ipc: fix waiting message

It got disabled by commit 439151bb5b0bd2ac4c9d2dd218fe377ce0b988e6.
ebuild-ipc: fix read timeout msg / daemon check

It got disabled in commit 06d31ef00da24352a6614f20bccfc892d2120ed9.