Various fixes to fix memory leaks after merging replication

tree with main.


sql/sql_binlog.cc:
  Adding code to free memory after execution of BINLOG statement.
  It caused a memory leak in the case that the execution failed
  for any reason.
sql/sql_class.cc:
  Since rli_fake is checked for NULL at various occations to mean
  that no rli_fake is assigned, NULL is assigned to rli_fake after
  deleting the instance.

sql/sql_class.cc

@@ -870,7 +870,10 @@ THD::~THD()
 #endif  
 #ifndef EMBEDDED_LIBRARY
   if (rli_fake)
+  {
     delete rli_fake;
+    rli_fake= NULL;
+  }
 #endif
 
   free_root(&main_mem_root, MYF(0));