Make inner class static

Found via error-prone.

apis/openstack-swift/src/test/java/org/jclouds/openstack/swift/v1/blobstore/RegionScopedSwiftBlobStoreParallelLiveTest.java

@@ -173,7 +173,7 @@ public class RegionScopedSwiftBlobStoreParallelLiveTest extends BaseBlobStoreInt
       }
    }
 
-   private final class RandomFileWriter implements Runnable {
+   private static final class RandomFileWriter implements Runnable {
       private final RandomAccessFile raf;
       private final long begin;
       private final long end;