Revert "Close FileChannels in UpdateHandler#copyFile."

This reverts commit 3e2670265e17e91c5a8cfff01711f973dccd2a0c.

It turns out that the behavior change in libcore was unintentional, and
it was already fixed [1].  Let's revert our workaround back to see if
the existing code is compatible with N.

  [1]: Ibacb192abc37870c74a2500d65b94d68f9c2318e
       5e7b572c2b494ab86ddd2baca3883a40a6064c1e

Bug: 26239281
Change-Id: I6cd2340492d93251231e7ee37c3d4f82c1721293
diff --git a/java/src/com/android/inputmethod/dictionarypack/UpdateHandler.java b/java/src/com/android/inputmethod/dictionarypack/UpdateHandler.java
index 6b32c68..0517bc8 100644
--- a/java/src/com/android/inputmethod/dictionarypack/UpdateHandler.java
+++ b/java/src/com/android/inputmethod/dictionarypack/UpdateHandler.java
@@ -689,16 +689,8 @@
         } else {
             try {
                 final FileChannel sourceChannel = ((FileInputStream) in).getChannel();
-                try {
-                    final FileChannel destinationChannel = ((FileOutputStream) out).getChannel();
-                    try {
-                        sourceChannel.transferTo(0, Integer.MAX_VALUE, destinationChannel);
-                    } finally {
-                        destinationChannel.close();
-                    }
-                } finally {
-                    sourceChannel.close();
-                }
+                final FileChannel destinationChannel = ((FileOutputStream) out).getChannel();
+                sourceChannel.transferTo(0, Integer.MAX_VALUE, destinationChannel);
             } catch (IOException e) {
                 // Can't work with channels, or something went wrong. Copy by hand.
                 DebugLogUtils.l("Won't work");