ib_acme: Use IPv4 rather than IPv6 when connecting to ACM server

When both IPv4 and IPv6 are running, getaddrinfo indicates IPv6
rather than IPv4 and that currently causes a failure to connect to
the ACM server.  Fix is to set the address family in the hint to
getaddrinfo to IPv4.

Signed-off-by: Hal Rosenstock <hal@mellanox.com>
Signed-off-by: Sean Hefty <sean.hefty@intel.com>