sheepdog: Use SocketAddress and socket_connect()

sheepdog: Use SocketAddress and socket_connect()

sd_parse_uri() builds a string from host and port parts for
inet_connect().  inet_connect() parses it into host, port and options.
Whether this gets exactly the same host, port and no options for all
inputs is not obvious.

Cut out the string middleman and build a SocketAddress for
socket_connect() instead.

Signed-off-by: Markus Armbruster <armbru@redhat.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>