Update third_party/nss to 3.15.5 Beta 2.

nss/lib/libpkix/pkix/top/pkix_build.c

 /* This Source Code Form is subject to the terms of the Mozilla Public
  * License, v. 2.0. If a copy of the MPL was not distributed with this
  * file, You can obtain one at http://mozilla.org/MPL/2.0/. */
 /*
  * pkix_build.c
  *
  * Top level buildChain function
  *
  */
 
@@ skipping 1330 matching lines @@
                             &nbioContext, &subjPubKey, &policyTree, NULL,
                             plContext);
 
         if (nbioContext != NULL) {
                 *pNBIOContext = nbioContext;
                 goto cleanup;
         }
 
         ERROR_CHECK(PKIX_CHECKCHAINFAILED);
 
-        if (state->reasonCode != 0) {
-                PKIX_ERROR(PKIX_CHAINREJECTEDBYREVOCATIONCHECKER);
-        }
+        /* XXX Remove this assertion after 2014-12-31. See bug 946984. */
+        PORT_Assert(state->reasonCode == 0);
 
         PKIX_CHECK(pkix_ValidateResult_Create
                 (subjPubKey, anchor, policyTree, &valResult, plContext),
                 PKIX_VALIDATERESULTCREATEFAILED);
 
         *pValResult = valResult;
         valResult = NULL;
 
 cleanup:
         PKIX_DECREF(subjPubKey);
@@ skipping 2483 matching lines @@
                 *pBuildResult = buildResult;
                 buildResult = NULL;
         }
 
 cleanup:
         PKIX_DECREF(buildResult);
         PKIX_DECREF(state);
 
         PKIX_RETURN(BUILD);
 }