Exception on openpty when starting buckd

Created by: andrewzhaosc

Java can throw LastErrorException even if openpty is successful.

I'm working on a PR to fix

I'm running on a KVM virtual machine on Google cloud

buckd: fatal error com.sun.jna.LastErrorException: [34] À
                                                         â¢
Exception in thread "main" java.lang.reflect.InvocationTargetException
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at com.facebook.buck.cli.bootstrapper.ClassLoaderBootstrapper.main(ClassLoaderBootstrapper.java:62)
Caused by: com.sun.jna.LastErrorException: [34] À
                                                 â¢
    at com.sun.jna.Native.invokeVoid(Native Method)
    at com.sun.jna.Function.invoke(Function.java:374)
    at com.sun.jna.Function.invoke(Function.java:323)
    at com.sun.jna.Library$Handler.invoke(Library.java:236)
    at com.sun.proxy.$Proxy0.openpty(Unknown Source)
    at com.facebook.buck.cli.Main.daemonizeIfPossible(Main.java:1750)
    at com.facebook.buck.cli.Main.access$4(Main.java:1711)
    at com.facebook.buck.cli.Main$DaemonBootstrap.main(Main.java:1771)
    ... 5 more