repl: Prevent crash when tab-completed with Proxy

If the proxy objects don't have a valid `hasOwnPropertyNames` trap,
REPL crashes with a `TypeError`, as per the bug report
https://github.com/nodejs/io.js/issues/2119

    > var proxy = Proxy.create({ fix: function() { return {}; } });
    undefined
    > proxy.<tab>
    TypeError: Proxy handler #<Object> has no 'getOwnPropertyNames' trap
        at Function.getOwnPropertyNames (native)
        at repl.js:644:40
        at REPLServer.defaultEval (repl.js:169:5)
        at bound (domain.js:254:14)
        at REPLServer.runBound [as eval] (domain.js:267:12)
        at REPLServer.complete (repl.js:639:14)
        at REPLServer.complete [as completer] (repl.js:207:10)
        at REPLServer.Interface._tabComplete (readline.js:377:8)
        at REPLServer.Interface._ttyWrite (readline.js:845:14)
        at ReadStream.onkeypress (readline.js:105:10)

This patch traps the error thrown and suppresses it.

PR-URL: https://github.com/nodejs/io.js/pull/2120
Fixes: https://github.com/nodejs/io.js/issues/2119


Reviewed-By: Colin Ihrig <cjihrig@gmail.com>
Reviewed-By: Evan Lucas <evanlucas@me.com>