xt_exit_row_locks() tries to release unallocated locks

Sometimes (e.g during table creation), xt_exit_row_locks() is called without the corresponding xt_init_row_locks() .
This leads to at attempt to release unallocated locks in
   xt_spinlock_free(NULL, &rl->rl_groups[i].lg_lock);

This makes Windows application verifier unhappy on x64.

Quick fix:
== verändert Datei storage/pbxt/src/lock_xt.cc
--- storage/pbxt/src/lock_xt.cc 2011-04-07 16:28:52 +0000
+++ storage/pbxt/src/lock_xt.cc 2011-05-13 22:56:00 +0000
@@ -726,11 +726,15 @@
   rl->rl_groups[i].lg_list_in_use = 0;
   rl->rl_groups[i].lg_list = NULL;
  }
+ rl->valid = 1;
  return OK;
 }

 void xt_exit_row_locks(XTRowLocksPtr rl)
 {
+ if (!rl->valid)
+ return;
+
  for (int i=0; i<XT_ROW_LOCK_GROUP_COUNT; i++) {
   xt_spinlock_free(NULL, &rl->rl_groups[i].lg_lock);
   rl->rl_groups[i].lg_wait_queue = NULL;
@@ -741,6 +745,7 @@
    rl->rl_groups[i].lg_list = NULL;
   }
  }
+ rl->valid = 0;
 }

 /*

=== verändert Datei storage/pbxt/src/lock_xt.h
--- storage/pbxt/src/lock_xt.h 2010-05-06 12:57:15 +0000
+++ storage/pbxt/src/lock_xt.h 2011-05-13 22:51:41 +0000
@@ -658,6 +658,7 @@
 struct XTLockWait;

 typedef struct XTRowLocks {
+ int valid;
  XTLockGroupRec rl_groups[XT_ROW_LOCK_GROUP_COUNT];

  void xt_cancel_temp_lock(XTLockWaitPtr lw);