Add ns_memcached:host_port/1 to get Erlang-formatted host info.
Add ns_memcached:host_port/1 to get Erlang-formatted host info.

This will be needed for ebucketmigrator.

Change-Id: I86b4f2d48899c6af5a2b1d4a4443badbad8376d8
Reviewed-on: http://review.membase.org/4352
Tested-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>
Reviewed-by: Aliaksey Kandratsenka <340b8e09ca65cd3fc686427fcfed17e87eaf61e2@gmail.com>

nimishzynga/ns_server,mschoch/ns_server,nimishzynga/ns_server,mschoch/ns_server,membase/ns_server,membase/ns_server,vzasade/ns_server,ceejatec/ns_server,mschoch/ns_server,ceejatec/ns_server,ceejatec/ns_server,daverigby/ns_server,mschoch/ns_server,t3rm1n4l/ns_server,daverigby/ns_server,nimishzynga/ns_server,ceejatec/ns_server,t3rm1n4l/ns_server,pavel-blagodov/ns_server,vzasade/ns_server,pavel-blagodov/ns_server,daverigby/ns_server,nimishzynga/ns_server,daverigby/ns_server,vzasade/ns_server,membase/ns_server,membase/ns_server,mschoch/ns_server,daverigby/ns_server,membase/ns_server,t3rm1n4l/ns_server,nimishzynga/ns_server,vzasade/ns_server,pavel-blagodov/ns_server,ceejatec/ns_server,nimishzynga/ns_server,t3rm1n4l/ns_server,mschoch/ns_server,membase/ns_server,t3rm1n4l/ns_server,ceejatec/ns_server,pavel-blagodov/ns_server