Cherry-picking patch for 12777649 from mysql-5.5

to mysql-5.5.16-release.

Original revision:
# revision-id: georgi.kodinov@oracle.com-20110812135004-3z3yjy7krf374clu
# parent: georgi.kodinov@oracle.com-20110812112536-dmh9i67tm8pqvz1a
# committer: Georgi Kodinov <Georgi.Kodinov@Oracle.com>
# branch nick: B12777649-5.5
# timestamp: Fri 2011-08-12 16:50:04 +0300
# message:
#   Bug #12777649: "OS THREAD ID" REMOVED 
#   
#   Pushed Calvin's patch.

sql/sql_class.cc

@@ -655,8 +655,8 @@ char *thd_security_context(THD *thd, char *buffer, unsigned int length,
   const char *proc_info= thd->proc_info;
 
   len= my_snprintf(header, sizeof(header),
-                   "MySQL thread id %lu, query id %lu",
-                   thd->thread_id, (ulong) thd->query_id);
+                   "MySQL thread id %lu, OS thread handle 0x%lx, query id %lu",
+                   thd->thread_id, (ulong) thd->real_id, (ulong) thd->query_id);
   str.length(0);
   str.append(header, len);