Windows : JVM Integration for Metrics : FileDescriptorRatioGaugeTest failure

There is FileDescriptorRatioGaugeTest failure as getOpenFileDescriptorCount() and getMaxFileDescriptorCount() are not available on Windows.


```
Metrics Parent .................................... SUCCESS [23.791s]
Annotations for Metrics ........................... SUCCESS [21.101s]
Metrics Core ...................................... SUCCESS [21.090s]
JVM Integration for Metrics ....................... FAILURE [2.254s]
```

```
-------------------------------------------------------------------------------
Test set: com.codahale.metrics.jvm.FileDescriptorRatioGaugeTest
-------------------------------------------------------------------------------
Tests run: 3, Failures: 1, Errors: 0, Skipped: 0, Time elapsed: 0.222 sec <<< FAILURE!
autoDetectsTheOperationSystemBean(com.codahale.metrics.jvm.FileDescriptorRatioGaugeTest)  Time elapsed: 0.004 sec  <<< FAILURE!
java.lang.AssertionError: expected:<NaN> to be less than or equal to:<1.0>
	at com.codahale.metrics.jvm.FileDescriptorRatioGaugeTest.autoDetectsTheOperationSystemBean(FileDescriptorRatioGaugeTest.java:64)
```