i tried to use centos 7 json file with packer , and i am getting handshaking error

[atul-ram]

2016/11/10 18:02:44 packer: 2016/11/10 18:02:44 Sending char 'e', code 101, shift false
2016/11/10 18:02:44 packer: 2016/11/10 18:02:44 Sending char 't', code 116, shift false
2016/11/10 18:02:44 packer: 2016/11/10 18:02:44 Sending char '.', code 46, shift false
2016/11/10 18:02:44 packer: 2016/11/10 18:02:44 Sending char 'i', code 105, shift false
2016/11/10 18:02:45 packer: 2016/11/10 18:02:45 Sending char 'f', code 102, shift false
2016/11/10 18:02:45 packer: 2016/11/10 18:02:45 Sending char 'n', code 110, shift false
2016/11/10 18:02:45 packer: 2016/11/10 18:02:45 Sending char 'a', code 97, shift false
2016/11/10 18:02:46 packer: 2016/11/10 18:02:46 Sending char 'm', code 109, shift false
2016/11/10 18:02:46 packer: 2016/11/10 18:02:46 Sending char 'e', code 101, shift false
2016/11/10 18:02:46 packer: 2016/11/10 18:02:46 Sending char 's', code 115, shift false
2016/11/10 18:02:47 packer: 2016/11/10 18:02:47 Sending char '=', code 61, shift false
2016/11/10 18:02:47 packer: 2016/11/10 18:02:47 Sending char '0', code 48, shift false
2016/11/10 18:02:47 packer: 2016/11/10 18:02:47 Special code '' found, replacing with: 65293
2016/11/10 18:02:47 packer: 2016/11/10 18:02:47 [INFO] Waiting for SSH, up to timeout: 1h0m0s
2016/11/10 18:02:47 ui: ==> qemu: Waiting for SSH to become available...
==> qemu: Waiting for SSH to become available...
2016/11/10 18:02:47 packer: 2016/11/10 18:02:47 [INFO] Attempting SSH connection...
2016/11/10 18:02:47 packer: 2016/11/10 18:02:47 reconnecting to TCP connection for SSH
2016/11/10 18:02:47 packer: 2016/11/10 18:02:47 handshaking with SSH
2016/11/10 18:03:47 packer: 2016/11/10 18:03:47 [DEBUG] SSH handshake err: Timeout during SSH handshake
2016/11/10 18:03:54 packer: 2016/11/10 18:03:54 [INFO] Attempting SSH connection...
2016/11/10 18:03:54 packer: 2016/11/10 18:03:54 reconnecting to TCP connection for SSH
2016/11/10 18:03:54 packer: 2016/11/10 18:03:54 handshaking with SSH