Mention NSPR libs in NSS version check error message.

base/nss_util.cc

Index: base/nss_util.cc
diff --git a/base/nss_util.cc b/base/nss_util.cc
index 13f61b603962b3c1252f302ecca5574d773f4ea5..c6c4ae3a6afc3448938cbc485ed88b26277e6af3 100644
--- a/base/nss_util.cc
+++ b/base/nss_util.cc
@@ -89,7 +89,9 @@ class NSSInitSingleton {
         nss_version_check_failed);
     // Also check the run-time NSS version.
     // NSS_VersionCheck is a >= check, not strict equality.
-    CHECK(NSS_VersionCheck("3.12.3")) << "We depend on NSS >= 3.12.3";
+    CHECK(NSS_VersionCheck("3.12.3")) << "We depend on NSS >= 3.12.3. "
+                                         "If NSS is up to date, please "
+                                         "update NSPR to the latest version.";
 
     SECStatus status = SECFailure;
 #if defined(USE_NSS_FOR_SSL_ONLY)