libcacard: fix resource leak

In function connect_to_qemu(), getaddrinfo() will allocate memory
that is stored into server, it should be freed by using freeaddrinfo()
before connect_to_qemu() return.

Cc: qemu-stable@nongnu.org
Reviewed-by: Markus Armbruster <armbru@redhat.com>
Signed-off-by: zhanghailiang <zhang.zhanghailiang@huawei.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
