Fix typo in Javadoc for onReadFromDisk

Change-Id: I7d8d683bd81fd96e826584cf502e418b29acab61
diff --git a/dalvik/src/main/java/dalvik/system/BlockGuard.java b/dalvik/src/main/java/dalvik/system/BlockGuard.java
index a7c59ca..d61f0e1 100644
--- a/dalvik/src/main/java/dalvik/system/BlockGuard.java
+++ b/dalvik/src/main/java/dalvik/system/BlockGuard.java
@@ -57,7 +57,7 @@
         void onWriteToDisk();
 
         /**
-         * Called on disk writes.
+         * Called on disk reads.
          */
         void onReadFromDisk();