testing theory that unmatched atomic increment/decrement is causing occasional tinderbox failures. See bug 126087.

security/nss/lib/pk11wrap/pk11skey.c

@@ -286,9 +286,7 @@ PK11_FreeSymKey(PK11SymKey *symKey)
 PK11SymKey *
 PK11_ReferenceSymKey(PK11SymKey *symKey)
 {
-    PK11_USE_THREADS(PZ_Lock(symKey->refLock);)
-    symKey->refCount++;
-    PK11_USE_THREADS(PZ_Unlock(symKey->refLock);)
+    PR_AtomicIncrement(&symKey->refCount);
     return symKey;
 }