Ensure the run integratin test script does not fail on linux. (#1640)
Ensure the run integratin test script does not fail on linux. (#1640)

The 'realpath' command fails on linix when the file does not exist (but does not fail on windows).
benwulfe/google-cloud-dotnet,benwulfe/google-cloud-dotnet,googleapis/google-cloud-dotnet,iantalarico/google-cloud-dotnet,googleapis/google-cloud-dotnet,chrisdunelm/google-cloud-dotnet,evildour/google-cloud-dotnet,jskeet/google-cloud-dotnet,evildour/google-cloud-dotnet,jskeet/google-cloud-dotnet,iantalarico/google-cloud-dotnet,evildour/google-cloud-dotnet,chrisdunelm/google-cloud-dotnet,googleapis/google-cloud-dotnet,chrisdunelm/google-cloud-dotnet,jskeet/google-cloud-dotnet,benwulfe/google-cloud-dotnet,jskeet/google-cloud-dotnet,chrisdunelm/gcloud-dotnet,jskeet/gcloud-dotnet,iantalarico/google-cloud-dotnet,jskeet/google-cloud-dotnet