MEDIUM: raw-sock: remove obsolete calls to fd_{cant,cond,done}_{send,recv}

MEDIUM: raw-sock: remove obsolete calls to fd_{cant,cond,done}_{send,recv}

Given that raw_sock's functions solely act on connections and that all its
callers properly use subscribe() when they want to receive/send more, there
is no more reason for calling fd_{cant,cond,done}_{send,recv} anymore as
this call is immediately overridden by the subscribe call. It's also worth
noting that the purpose of fd_cond_recv() whose purpose was to speculatively
enable reading in the FD cache if the FD was active but not yet polled was
made to save on expensive epoll_ctl() calls and was implicitly covered more
cleanly by recent commit 5d7dcc2a8e ("OPTIM: epoll: always poll for recv if
neither active nor ready").

No change on the number of calls to epoll_ctl() was noticed consecutive to
this change.