Update the NSS bug number for the invalid read when AES-CBC decrypting.

crypto/encryptor_nss.cc

Index: crypto/encryptor_nss.cc
===================================================================
--- crypto/encryptor_nss.cc	(revision 226247)
+++ crypto/encryptor_nss.cc	(working copy)
@@ -101,7 +101,7 @@
   if (ciphertext.size() % AES_BLOCK_SIZE != 0) {
     // Decryption will fail if the input is not a multiple of the block size.
     // PK11_CipherOp has a bug where it will do an invalid memory access before
-    // the start of the input, so avoid calling it. (Possibly NSS bug 921687).
+    // the start of the input, so avoid calling it. (NSS bug 922780).
     plaintext->clear();
     return false;
   }