Fix a Valgrind leak error report for not freed binlog injector singleton.

sql/mysqld.cc:
  Free the binlog injector singleton during shutdown.
sql/rpl_injector.cc:
  Add free_instance() method.
sql/rpl_injector.h:
  Add free_instance() method.

sql/mysqld.cc

@@ -28,6 +28,10 @@
 
 #include "ha_myisam.h"
 
+#ifdef HAVE_ROW_BASED_REPLICATION
+#include "rpl_injector.h"
+#endif
+
 #ifdef WITH_INNOBASE_STORAGE_ENGINE
 #define OPT_INNODB_DEFAULT 1
 #else
@@ -1183,6 +1187,9 @@ void clean_up(bool print_message)
     what they have that is dependent on the binlog
   */
   ha_binlog_end(current_thd);
+#ifdef HAVE_ROW_BASED_REPLICATION
+  injector::free_instance();
+#endif
   mysql_bin_log.cleanup();
 
 #ifdef HAVE_REPLICATION

sql/rpl_injector.cc

@@ -155,6 +155,16 @@ injector *injector::instance()
   return s_injector;
 }
 
+void injector::free_instance()
+{
+  injector *inj = s_injector;
+
+  if (inj != 0)
+  {
+    s_injector= 0;
+    delete inj;
+  }
+}
 
 
 injector::transaction injector::new_trans(THD *thd)

sql/rpl_injector.h

@@ -59,6 +59,11 @@ class injector
   */
   static injector *instance();
 
+  /*
+    Delete the singleton instance (if allocated). Used during server shutdown.
+  */
+  static void free_instance();
+
     /*
       A transaction where rows can be added.