Merge pull request #135 from square/jwilson/flush

Track DiskLruCache.flush change.

okhttp/src/main/java/com/squareup/okhttp/internal/DiskLruCache.java

@@ -555,6 +555,7 @@ public final class DiskLruCache implements Closeable {
       lruEntries.remove(entry.key);
       journalWriter.write(REMOVE + ' ' + entry.key + '\n');
     }
+    journalWriter.flush();
 
     if (size > maxSize || journalRebuildRequired()) {
       executorService.submit(cleanupCallable);