rpc client can not deal with ENOSOCK, so translate it into ENOCONN

rpc client can not deal with ENOSOCK, so translate it into ENOCONN

commit 5fe46e9d733f19a880ef7e516002bd4c2b833e14 upstream.

If NFSv4 client send a request before connect, or the old connection was broken
because a ETIMEOUT error catched by call_status, ->send_request will return
ENOSOCK, but rpc layer can not deal with it, so make sure ->send_request can
translate ENOSOCK into ENOCONN.

Signed-off-by: Bian Naimeng <biannm@cn.fujitsu.com>
Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>
Cc: Chuck Lever <chuck.lever@oracle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>