Suppress yet another wrong-locking report in NSS

BUG=61585
TBR=glider
Review URL: http://codereview.chromium.org/4339003

git-svn-id: svn://svn.chromium.org/chrome/trunk/src@64951 0039d316-1c4b-4281-b951-d872f2087c98

tools/valgrind/tsan/suppressions.txt

@@ -147,7 +147,7 @@
 }
 
 {
-  bug_61585
+  bug_61585a
   ThreadSanitizer:UnlockForeign
   fun:pthread_mutex_destroy
   ...
@@ -156,6 +156,18 @@
   fun:*AtExitManager*
 }
 
+{
+  bug_61585b
+  ThreadSanitizer:UnlockNonLocked
+  fun:pthread_mutex_unlock
+  fun:PR_Unlock
+  fun:nssSession_ExitMonitor
+  fun:find_objects
+  ...
+  fun:nssTrustDomain_FindCertificatesBySubject
+  ...
+}
+
 {
   bug_61753
   ThreadSanitizer:Race