* kdb_dbm.c: Ditch DB_OPENCLOSE conditionals, and fix the real

	* kdb_dbm.c: Ditch DB_OPENCLOSE conditionals, and fix the real
 	problem.  Like the policy db, the main db is now opened on first
 	lock and closed on last unlock.
	Set db_dbm_ctx to NULL after closing it, to help detect dangling
	references.
	(krb5_dbm_db_put_principal, krb5_dbm_db_delete_principal):
 	KDBM_STORE can fail (in case of database corruption, for example)
 	*without* causing errno to be set.  If errno is zero, use
 	KRB5_KDB_DB_CORRUPT instead. (If it is non-zero, it may still be
 	wrong, but at least something gets reported. This will be properly
	fixed by ditching KDBM_* altogether, and using the non-lossy db
	interfaces, so it's a good enough fix for now.)
	(krb5_dbm_db_rename): grab errno from rename *before*
 	calling krb5_dbm_db_end_update, to avoid "not a typewriter"
 	syndrome.
 	(krb5_dbm_db_unlock): only close on zero refcount.

git-svn-id: svn://anonsvn.mit.edu/krb5/trunk@9400 dc483132-0cff-0310-8789-dd5450dbe970