[vlc-devel] [PATCH] access/sftp: authenticate with ssh-agent, and check libssh2_userauth_list for available authentication methods

[Yidong Ren]

This is update of
https://mailman.videolan.org/pipermail/vlc-devel/2017-January/111116.html
This patch allows authenticate to sftp server with ssh-agent.
Thanks Denis Charmet for his suggestions:
    libssh2_agent_free(NULL) will crash, according to
https://github.com/libssh2/libssh2/blob/master/src/agent.c#L806. Fixed.
    Duplicated authentication choice was removed.