smb: client: fix hang in wait_for_response() for negproto

Call cifs_reconnect() to wake up processes waiting on negotiate
protocol to handle the case where server abruptly shut down and had no
chance to properly close the socket.

Simple reproducer:

  ssh 192.168.2.100 pkill -STOP smbd
  mount.cifs //192.168.2.100/test /mnt -o ... [never returns]

Cc: Rickard Andersson <rickaran@axis.com>
Signed-off-by: Paulo Alcantara (Red Hat) <pc@manguebit.com>
Signed-off-by: Steve French <stfrench@microsoft.com>