fix the panic when "ps -a" with dead containers
fix the panic when "ps -a" with dead containers

Signed-off-by: Shijiang Wei <d51735f6fb3b158a0436903895ceec01381bfb9f@gmail.com>

jzwlqx/denverdino.github.io,resouer/swarm,gdevillele/docker.github.io,anweiss/docker.github.io,joeuo/docker.github.io,phiroict/docker,joaofnfernandes/docker.github.io,joaofnfernandes/docker.github.io,moxiegirl/swarm,shin-/docker.github.io,sfsmithcha/swarm,docker-zh/docker.github.io,denverdino/denverdino.github.io,doronp/swarm,docker/docker.github.io,londoncalling/docker.github.io,sfsmithcha/swarm,qianzhangxa/swarm,barais/swarm,LuisBosquez/docker.github.io,LuisBosquez/docker.github.io,gdevillele/docker.github.io,JimGalasyn/docker.github.io,alexisbellido/docker.github.io,CodeNow/swarm,atlassian/swarm,sanscontext/docker.github.io,BSWANG/denverdino.github.io,gdevillele/docker.github.io,fugr/swarm,morpheyesh/swarm,bdwill/docker.github.io,denverdino/docker.github.io,mgoelzer/swarm,atlassian/swarm,BSWANG/denverdino.github.io,BSWANG/denverdino.github.io,linecheng/swarm,aduermael/docker.github.io,jimmycmh/swarm,CiaranCostello/swarm,allencloud/swarm,LuisBosquez/docker.github.io,qianzhangxa/swarm,joeuo/docker.github.io,jimmycmh/swarm,rchicoli/swarm,jzwlqx/denverdino.github.io,johnstep/docker.github.io,sanscontext/docker.github.io,docker-zh/docker.github.io,bdwill/docker.github.io,schmunk42/swarm,liubin/swarm,LukasBacigal/swarm,shin-/docker.github.io,shubheksha/docker.github.io,rillig/docker.github.io,LuisBosquez/docker.github.io,londoncalling/docker.github.io,JimGalasyn/docker.github.io,liubin/swarm,johnstep/docker.github.io,riuvshin/swarm,MHBauer/swarm,menglingwei/denverdino.github.io,allencloud/swarm,kyhavlov/swarm,kunalkushwaha/swarm,denverdino/docker.github.io,CodeNow/swarm,johnstep/docker.github.io,danix800/docker.github.io,phiroict/docker,linecheng/swarm,docker/docker.github.io,gdevillele/docker.github.io,aduermael/docker.github.io,londoncalling/docker.github.io,gdevillele/docker.github.io,joaofnfernandes/docker.github.io,moxiegirl/swarm,gradywang/swarm,londoncalling/docker.github.io,gradywang/swarm,menglingwei/denverdino.github.io,denverdino/denverdino.github.io,menglingwei/denverdino.github.io,denverdino/docker.github.io,docker-zh/docker.github.io,BSWANG/denverdino.github.io,alexisbellido/docker.github.io,rchicoli/swarm,LuisBosquez/docker.github.io,danix800/docker.github.io,sanscontext/docker.github.io,BSWANG/denverdino.github.io,shin-/docker.github.io,JimGalasyn/docker.github.io,shubheksha/docker.github.io,jzwlqx/denverdino.github.io,JimGalasyn/docker.github.io,xFragger/swarm,thaJeztah/docker.github.io,joeuo/docker.github.io,joeuo/docker.github.io,rillig/docker.github.io,echupriyanov/swarm,docker/docker.github.io,ezrasilvera/swarm,thaJeztah/docker.github.io,JimGalasyn/docker.github.io,bdwill/docker.github.io,phiroict/docker,CiaranCostello/swarm,londoncalling/docker.github.io,alexisbellido/docker.github.io,denverdino/denverdino.github.io,joeuo/docker.github.io,echupriyanov/swarm,danix800/docker.github.io,rancher/swarm,alexisbellido/docker.github.io,phiroict/docker,rillig/docker.github.io,denverdino/docker.github.io,anweiss/docker.github.io,ch3lo/swarm,shubheksha/docker.github.io,johnstep/docker.github.io,schmunk42/swarm,fugr/swarm,ch3lo/swarm,alexisbellido/docker.github.io,docker-zh/docker.github.io,doronp/swarm,shubheksha/docker.github.io,menglingwei/denverdino.github.io,LukasBacigal/swarm,shin-/docker.github.io,thaJeztah/docker.github.io,shin-/docker.github.io,bdwill/docker.github.io,barais/swarm,menglingwei/denverdino.github.io,danix800/docker.github.io,troy0820/docker.github.io,troy0820/docker.github.io,anweiss/docker.github.io,docker/docker.github.io,thaJeztah/docker.github.io,denverdino/denverdino.github.io,denverdino/docker.github.io,megamsys/swarm,rillig/docker.github.io,jzwlqx/denverdino.github.io,phiroict/docker,joaofnfernandes/docker.github.io,aduermael/docker.github.io,mgoelzer/swarm,docker-zh/docker.github.io,shubheksha/docker.github.io,Spritekin/swarm,docker/docker.github.io,rancher/swarm,anweiss/docker.github.io,xFragger/swarm,sanscontext/docker.github.io,joaofnfernandes/docker.github.io,thaJeztah/docker.github.io,denverdino/denverdino.github.io,ezrasilvera/swarm,resouer/swarm,kyhavlov/swarm,aduermael/docker.github.io,sanscontext/docker.github.io,swarm-hooks/swarm,Spritekin/swarm,johnstep/docker.github.io,auzias/swarm,morpheyesh/swarm,troy0820/docker.github.io,jzwlqx/denverdino.github.io,auzias/swarm,riuvshin/swarm,MHBauer/swarm,swarm-hooks/swarm,bdwill/docker.github.io,kunalkushwaha/swarm,troy0820/docker.github.io,anweiss/docker.github.io,megamsys/swarm