The "mysql client in mysqld"(which is used by
replication and federated) should use alarms instead of setting
socket timeout value if the rest of the server uses alarm. By
always calling 'my_net_set_write_timeout'
or 'net_set_read_timeout' when changing the timeout value(s), the
selection whether to use alarms or timeouts will be handled by
ifdef's in those two functions.

This is minimal backport of patch for BUG#26664, which was pushed
to 5.0 and up.

Affects 4.1 only.