communicator/ssh: fix nil ptr error
communicator/ssh: fix nil ptr error

fixes a case where we could return a nil error and nil ssh session.

ricardclau/packer,dave2/packer,smaato/packer,ricardclau/packer,pieter-lazzaro/packer,KohlsTechnology/packer,atlassian/packer,ChrisLundquist/packer,zhuzhih2017/packer,quantang/packer,p1-nico/packer,mkuzmin/packer,hashicorp/packer,tb3088/packer,arizvisa/packer,mafrosis/packer,boumenot/packer,tb3088/packer,atlassian/packer,pvandervelde/packer,youhong316/packer,tsmolka/packer,youhong316/packer,sean-/packer,markpeek/packer,tas50/packer,rnaveiras/packer,grubernaut/packer,markpeek/packer,atlassian/packer,timsutton/packer,pieter-lazzaro/packer,tas50/packer,arizvisa/packer,zhuzhih2017/packer,jen20/packer,dayglojesus/packer,tsmolka/packer,timsutton/packer,KohlsTechnology/packer,quantang/packer,sean-/packer,smaato/packer,taliesins/packer,bryson/packer,boumenot/packer,arizvisa/packer,bryson/packer,pvandervelde/packer,paulmey/packer,quantang/packer,jen20/packer,timsutton/packer,routelastresort/packer,p1-nico/packer,paulmey/packer,routelastresort/packer,rnaveiras/packer,youhong316/packer,taliesins/packer,zhuzhih2017/packer,zhuzhih2017/packer,dave2/packer,grubernaut/packer,quantang/packer,markpeek/packer,mitchellh/packer,p1-nico/packer,tb3088/packer,tas50/packer,dave2/packer,tas50/packer,bryson/packer,smaato/packer,grubernaut/packer,KohlsTechnology/packer,sean-/packer,ChrisLundquist/packer,p1-nico/packer,mafrosis/packer,dayglojesus/packer,atlassian/packer,bryson/packer,paulmey/packer,ChrisLundquist/packer,ricardclau/packer,c22/packer,zhuzhih2017/packer,zhuzhih2017/packer,pecigonzalo/packer,quantang/packer,rnaveiras/packer,ricardclau/packer,tas50/packer,boumenot/packer,taliesins/packer,tsmolka/packer,markpeek/packer,pvandervelde/packer,tsmolka/packer,KohlsTechnology/packer,dave2/packer,atlassian/packer,c22/packer,smaato/packer,mkuzmin/packer,pecigonzalo/packer,mitchellh/packer,smaato/packer,sean-/packer,mitchellh/packer,rnaveiras/packer,paulmey/packer,dayglojesus/packer,KohlsTechnology/packer,pieter-lazzaro/packer,hashicorp/packer,grubernaut/packer,hashicorp/packer,pieter-lazzaro/packer,hashicorp/packer,mafrosis/packer,tsmolka/packer,youhong316/packer,dayglojesus/packer,jen20/packer,timsutton/packer,boumenot/packer,taliesins/packer,c22/packer,dayglojesus/packer,routelastresort/packer,pieter-lazzaro/packer,ChrisLundquist/packer,paulmey/packer,routelastresort/packer,mkuzmin/packer,p1-nico/packer,mkuzmin/packer,arizvisa/packer,timsutton/packer,KohlsTechnology/packer,sean-/packer,pvandervelde/packer,grubernaut/packer,markpeek/packer,markpeek/packer,tsmolka/packer,bryson/packer,mkuzmin/packer,pvandervelde/packer,youhong316/packer,mkuzmin/packer,ChrisLundquist/packer,tb3088/packer,ChrisLundquist/packer,mafrosis/packer,pecigonzalo/packer,boumenot/packer,mitchellh/packer,taliesins/packer,ricardclau/packer,arizvisa/packer,pieter-lazzaro/packer,paulmey/packer,mitchellh/packer,jen20/packer,pecigonzalo/packer,tas50/packer,c22/packer,c22/packer,sean-/packer,rnaveiras/packer,grubernaut/packer,jen20/packer,dave2/packer,timsutton/packer,tb3088/packer,dave2/packer,p1-nico/packer,bryson/packer,rnaveiras/packer,youhong316/packer,ricardclau/packer,taliesins/packer,c22/packer,atlassian/packer,jen20/packer,routelastresort/packer,pvandervelde/packer,arizvisa/packer,tb3088/packer,mafrosis/packer,smaato/packer