go/oasis-test-runner/cmd: Don't print error messages twice

Previously, Execute() called nodeCommon.EarlyLogAndExit() if there was
an error running rootCmd.Execute() which in turn printed the error to
stderr resulting in the same error message being printed twice.

go/oasis-test-runner/cmd/root.go

@@ -75,7 +75,7 @@ func RootCmd() *cobra.Command {
 // Execute spawns the main entry point after handing the config file.
 func Execute() {
 	if err := rootCmd.Execute(); err != nil {
-		nodeCommon.EarlyLogAndExit(err)
+		os.Exit(1)
 	}
 }