pull up r20040 from trunk

pull up r20040 from trunk

 r20040@cathode-dark-space:  jaltman | 2007-10-01 16:09:55 -0400
 ticket: new
 subject: remove error tables by pointer
 tags: pullup
 target_version: 1.6.3

 On Windows, it is possible for the same DLL to be loaded
 into a process multiple times as separate instances.  Each
 time a DLL is loaded it registers its error tables at different
 locations in the process address space.  Removing the tables
 by base instead of pointer value can result in the error table
 list pointing at invalid memory.

ticket: 5801
version_fixed: 1.6.3

git-svn-id: svn://anonsvn.mit.edu/krb5/branches/krb5-1-6@20079 dc483132-0cff-0310-8789-dd5450dbe970