Reduce showmount timeouts.

Reduce showmount timeouts.

Showmount itself tries to use a short timeout but
the RPC clnttcp_create and clntudp_create calls will call portmap
internally to get the port to use if it is set to 0 in the passed
address structure. The above calls then use the internal timeouts,
 basically 60 seconds, which slows things down. Also the for tcp a
blocking connect is used which can take quite a while to timeout as
well.

showmount tries tcp then udp so a fail can go through several lengthy
waits before failing.

I've grabbed some of the autofs code and put together a patch to allow
specification of the timeouts for the portmap getport and to implement a
non-blocking connect.

Signed-off-by: Neil Brown <neilb@suse.de>