Improve comments around FLUSH STATUS

It's not possible to flush the global status variables in 5.0
Update test case so it works by recording the value of handle_rollback
before and compare it to the value after


mysql-test/r/innodb_mysql.result:
  Update result file
mysql-test/t/innodb_mysql.test:
  It's not possible to reset the global status variables in 5.0 so intead its value
  is recorded and compared to the after value.
  It should not have changed.
sql/mysqld.cc:
  Improve comments
sql/set_var.cc:
  Improve comments
sql/sql_class.cc:
  Improve comments
sql/sql_class.h:
  Improve comments

1 files changed, 2 insertions, 3 deletions

diff --git a/sql/sql_class.cc b/sql/sql_class.cc
index f5bab1d17f4..ba2f525a4a4 100644
--- a/sql/sql_class.cc
+++ b/sql/sql_class.cc
@@ -464,14 +464,13 @@ THD::~THD()
 
 void add_to_status(STATUS_VAR *to_var, STATUS_VAR *from_var)
 {
-  ulong *end= (ulong*) ((byte*) to_var + offsetof(STATUS_VAR,
-						  last_system_status_var) +
+  ulong *end= (ulong*) ((byte*) to_var +
+                        offsetof(STATUS_VAR, last_system_status_var) +
 			sizeof(ulong));
   ulong *to= (ulong*) to_var, *from= (ulong*) from_var;
 
   while (to != end)
     *(to++)+= *(from++);
-  /* it doesn't make sense to add last_query_cost values */
 }