Catch unknown process id exception in impala_cluster to fix intermittent process test failures.
Catch unknown process id exception in impala_cluster to fix intermittent process test failures.

ibmsoe/ImpalaPPC,scalingdata/Impala,tempbottle/Impala,ImpalaToGo/ImpalaToGo,andybab/Impala,rdblue/Impala,AtScaleInc/Impala,lnliuxing/Impala,bowlofstew/Impala,caseyching/Impala,ImpalaToGo/ImpalaToGo,AtScaleInc/Impala,XiaominZhang/Impala,tempbottle/Impala,gerashegalov/Impala,mapr/impala,lirui-intel/Impala,placrosse/ImpalaToGo,theyaa/Impala,henryr/Impala,andybab/Impala,rdblue/Impala,ImpalaToGo/ImpalaToGo,scalingdata/Impala,tempbottle/Impala,caseyching/Impala,theyaa/Impala,ibmsoe/ImpalaPPC,AtScaleInc/Impala,gistic/PublicSpatialImpala,gerashegalov/Impala,bowlofstew/Impala,ImpalaToGo/ImpalaToGo,cloudera/recordservice,XiaominZhang/Impala,XiaominZhang/Impala,cgvarela/Impala,bratatidas9/Impala-1,lirui-intel/Impala,cchanning/Impala,cchanning/Impala,placrosse/ImpalaToGo,ibmsoe/ImpalaPPC,tempbottle/Impala,cloudera/recordservice,grundprinzip/Impala,kapilrastogi/Impala,bowlofstew/Impala,ibmsoe/ImpalaPPC,kapilrastogi/Impala,lnliuxing/Impala,placrosse/ImpalaToGo,cchanning/Impala,rdblue/Impala,placrosse/ImpalaToGo,lirui-intel/Impala,brightchen/Impala,cgvarela/Impala,brightchen/Impala,lnliuxing/Impala,bowlofstew/Impala,andybab/Impala,gerashegalov/Impala,placrosse/ImpalaToGo,rdblue/Impala,bratatidas9/Impala-1,rampage644/impala-cut,rampage644/impala-cut,grundprinzip/Impala,bratatidas9/Impala-1,bratatidas9/Impala-1,bratatidas9/Impala-1,rdblue/Impala,henryr/Impala,bowlofstew/Impala,scalingdata/Impala,rdblue/Impala,caseyching/Impala,cloudera/recordservice,theyaa/Impala,rampage644/impala-cut,grundprinzip/Impala,cgvarela/Impala,gistic/PublicSpatialImpala,bratatidas9/Impala-1,andybab/Impala,mapr/impala,lirui-intel/Impala,theyaa/Impala,placrosse/ImpalaToGo,henryr/Impala,cchanning/Impala,cgvarela/Impala,kapilrastogi/Impala,brightchen/Impala,gerashegalov/Impala,cchanning/Impala,caseyching/Impala,grundprinzip/Impala,XiaominZhang/Impala,gerashegalov/Impala,mapr/impala,rampage644/impala-cut,XiaominZhang/Impala,lirui-intel/Impala,cgvarela/Impala,lnliuxing/Impala,henryr/Impala,kapilrastogi/Impala,andybab/Impala,XiaominZhang/Impala,ibmsoe/ImpalaPPC,cgvarela/Impala,caseyching/Impala,lnliuxing/Impala,henryr/Impala,kapilrastogi/Impala,rampage644/impala-cut,cgvarela/Impala,gistic/PublicSpatialImpala,scalingdata/Impala,lirui-intel/Impala,cloudera/recordservice,brightchen/Impala,rdblue/Impala,ibmsoe/ImpalaPPC,scalingdata/Impala,AtScaleInc/Impala,cloudera/recordservice,gerashegalov/Impala,AtScaleInc/Impala,theyaa/Impala,cloudera/recordservice,gistic/PublicSpatialImpala,theyaa/Impala,henryr/Impala,kapilrastogi/Impala,grundprinzip/Impala,kapilrastogi/Impala,bowlofstew/Impala,mapr/impala,caseyching/Impala,bowlofstew/Impala,AtScaleInc/Impala,grundprinzip/Impala,gistic/PublicSpatialImpala,brightchen/Impala,tempbottle/Impala,theyaa/Impala,scalingdata/Impala,lnliuxing/Impala,brightchen/Impala,ibmsoe/ImpalaPPC,rampage644/impala-cut,bratatidas9/Impala-1,gistic/PublicSpatialImpala,cchanning/Impala,lirui-intel/Impala,mapr/impala,gerashegalov/Impala,ImpalaToGo/ImpalaToGo,ImpalaToGo/ImpalaToGo,caseyching/Impala,tempbottle/Impala,brightchen/Impala,andybab/Impala,cloudera/recordservice,XiaominZhang/Impala,cchanning/Impala,lnliuxing/Impala,tempbottle/Impala