[bug] failed to start Pouch Daemon

[allencloud]

Issue Description

When I run Pouch Daemon on linux machine, I ran into such as a situation:

root@ubuntu:~/go/src/github.com/alibaba/pouch# ./pouchd
ERRO[2017-11-03 15:55:04.312329177] failed to new containerd's client: failed to connect containerd: failed to dial "/var/run/containerd.sock": dial unix /var/run/containerd.sock: connect: connection refused
ERRO[2017-11-03 15:55:04.317246405] failed to wait process: /usr/local/bin/containerd, signal: killed
WARN[2017-11-03 15:55:04.317710458] process: /usr/local/bin/containerd exited
Error: failed to new daemon
Usage:
   [flags]

Flags:
  -c, --containerd string          where does containerd listened on (default "/var/run/containerd.sock")
      --containerd-config string   Specify the path of Containerd binary (default "/etc/containerd/config.toml")
      --containerd-path string     Specify the path of Containerd binary (default "/usr/local/bin/containerd")
  -D, --debug                      switch debug level
  -h, --help                       help for this command
      --home-dir string            The pouchd's home directory (default "/etc/pouchd")
  -l, --listen stringArray         which address to listen on (default [unix:///var/run/pouchd.sock])

It seems that the inner config to setup between pouchd and containerd causes this error.
In addition, I was confused that when pouch daemon met an error, it would throw out the following things:

Usage:
   [flags]

Flags:
  -c, --containerd string          where does containerd listened on (default "/var/run/containerd.sock")
      --containerd-config string   Specify the path of Containerd binary (default "/etc/containerd/config.toml")
      --containerd-path string     Specify the path of Containerd binary (default "/usr/local/bin/containerd")
  -D, --debug                      switch debug level
  -h, --help                       help for this command
      --home-dir string            The pouchd's home directory (default "/etc/pouchd")
  -l, --listen stringArray         which address to listen on (default [unix:///var/run/pouchd.sock])

Describe what happened:
Pouchd failed to start up.

Describe what you expected to happen:
Pouch works to start up.

How to reproduce it (as minimally and precisely as possible):

1. build pouchd binary via make build
2. execute ./pouchd

Anything else we need to know?:
NONE

Environment:

• pouch version (use pouch version): NONE
• OS (e.g. from /etc/os-release): ubuntu 16.04
• Kernel (e.g. uname -a): Linux ubuntu 4.4.0-97-generic [docs] Missed Usage and System Design Documentation in README #120-Ubuntu SMP Tue Sep 19 17:28:18 UTC 2017 x86_64 x86_64 x86_64 GNU/Linux
• Install tools: NONE
• Others: NONE

[Ace-Tang]

how about do a config file for pouch? ping @allencloud @skoo87

[allencloud]

Can't agree more @Ace-Tang
If you are determined to do that, please first open a proposal issue and start to work on that.
Thanks a lot.