Correct NDK docs for MediaDrm#getKeyRequest

The header comment says that the default URL is returned, but it
is not.  The comment has been corrected.

bug:35257669
Change-Id: Ica6c60382f68d8a70aeab8959eb29cf454ff931b
diff --git a/include/ndk/NdkMediaDrm.h b/include/ndk/NdkMediaDrm.h
index 9dd6283..cba4380 100644
--- a/include/ndk/NdkMediaDrm.h
+++ b/include/ndk/NdkMediaDrm.h
@@ -159,8 +159,7 @@
  * to obtain or release keys used to decrypt encrypted content.
  * AMediaDrm_getKeyRequest is used to obtain an opaque key request byte array that
  * is delivered to the license server.  The opaque key request byte array is
- * returned in KeyRequest.data.  The recommended URL to deliver the key request to
- * is returned in KeyRequest.defaultUrl.
+ * returned in KeyRequest.data.
  *
  * After the app has received the key request response from the server,
  * it should deliver to the response to the DRM engine plugin using the method