bugfix: fix daemon panic when meta snapshotter is nil

[oiooj]

fix #1139

[CLAassistant]

All committers have signed the CLA.

[codecov-io]

Codecov Report

Merging #1140 into master will increase coverage by 0.85%.
The diff coverage is 0%.

@@            Coverage Diff             @@
##           master    #1140      +/-   ##
==========================================
+ Coverage   14.75%   15.61%   +0.85%     
==========================================
  Files         172      172              
  Lines        9628     9688      +60     
==========================================
+ Hits         1421     1513      +92     
+ Misses       8102     8067      -35     
- Partials      105      108       +3

Impacted Files	Coverage Δ
daemon/mgr/container.go	4.59% <0%> (-0.01%)	⬇️
pkg/utils/utils.go	78.15% <0%> (-1.85%)	⬇️
cli/command.go	0% <0%> (ø)	⬆️
cli/cli.go	0% <0%> (ø)	⬆️
client/client.go	46.66% <0%> (+10.3%)	⬆️

[HusterWan]

LGTM

[allencloud]

Thanks a lot for your contribution. This is exactly what we need. While we encourage that provide more details about the pull request description to illustrate what you did. @oiooj
Maybe next time, more info is better. Thanks again.