Only create /tmp/augcmds.txt if it doesn't exist
Only create /tmp/augcmds.txt if it doesn't exist

Nothing deep; just trying to keep Mercurial from marking the file as
modified as I change the commands that try runs

lutter/augeas,pevalme/augeas,bkearney/augeas,raphink/augeas,camptocamp/augeas,ptoscano/augeas,lutter/augeas,hercules-team/augeas-do-not-use,mchf/augeas,jjlin/augeas,kunkku/augeas,jjlin/augeas,kumy/augeas,MikaelSmith/augeas,MikaelSmith/augeas,ptoscano/augeas,jtopjian/augeas,GeoffWilliams/augeas,kunkku/augeas,jtopjian/augeas,camptocamp/augeas,bkearney/augeas,hercules-team/augeas-do-not-use,ptoscano/augeas,mlichvar/augeas,mlichvar/augeas,dafugg/augeas,manandbytes/augeas,camptocamp/augeas,kumy/augeas,hercules-team/augeas,dafugg/augeas,manandbytes/augeas,domcleal/augeas,bkearney/augeas,raphink/augeas,domcleal/augeas,pevalme/augeas,domcleal/augeas,pevalme/augeas,lutter/augeas,jasperla/augeas,hercules-team/augeas-do-not-use,jjlin/augeas,kumy/augeas,bkearney/augeas,jasperla/augeas,GeoffWilliams/augeas,dafugg/augeas,hercules-team/augeas,mchf/augeas,mlichvar/augeas,kunkku/augeas,kumy/augeas,camptocamp/augeas