ssh error: connection to **** exited: No auth methods could be used.

[renhongtao]

Error when use ssh in this code to connect other device.
no ask any input info,then just exit with error info next.

exited: No auth methods could be used.

sysinfo: Linux version 3.10.65 (gcc version 4.9.x-google 20140827 (mtk-20150409) (GCC) )