virt: add func 'get_uri_with_transport' into libvirt_vm.

get_uri_with_transport(origin_uri="qemu:///system", transport="",
                            dest_ip=""):
    """
    Return a URI to connect driver on dest with a specificed transport.

    @param origin_uri: The URI on dest used to connect itself directly.
    @param transport: The transport type connect to dest.
    @param dest_ip: The ip of destination.
    """

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
virt: fixup virsh connect test module.

changes from v1:
    remote_root_pwd > remote_pwd.
    session.a_id > session.get_id().
    seperate uri parsing code into libvirt_vm.
    pass test.tmpdir to utils_conn module.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
virt: fixup virsh connect configuration module.

changes from v1:
    remote_root_pwd > remote_pwd.
    remove a duplicate line.

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>
virt: fixup utils_conn module.

changes from v1:
    add tmp_dir as a para in __init__ of connection class.
    remove TLSSCPClientError and TLSSCPServerError.
    rebuild the TLSSCPError

Signed-off-by: yangdongsheng <yangds.fnst@cn.fujitsu.com>