fmsg: support temporarily withholding output

Trying to print to a shared stdout is a terrible idea. This change makes it possible to withhold output for the lifetime of the sandbox.

Signed-off-by: Ophestra Umiker <cat@ophivana.moe>

state.go

@@ -30,6 +30,6 @@ func tryState() {
 			fmt.Println("No information available")
 		}
 
-		os.Exit(0)
+		fmsg.Exit(0)
 	}
 }