(ITS#7179) pcache ttr issues

[mhardin@symas.com]

Full_Name: Matthew Hardin
Version: 2.4.29
OS: Linux (Debian 6, x86_64)
URL: ftp://ftp.openldap.org/incoming/
Submission from: (NULL) (170.215.93.127)


When proxycache overlay is configured with a time-to-refresh (TTR) value and the
entry being refreshed is no longer available on the remote server, the refresh
operation continues sending ldap search requests to the server, to which the
server responds with an error 2 and a text of "invalid deref".

The following log excerpt is from the remote server:

4f3f7580 conn=1003 op=55 SRCH base="ou=people,dc=example,dc=com" scope=1 deref=0
filter="(&(objectClass=posixAccount)(uidNumber=10001))"
4f3f7580 conn=1003 op=55 SRCH attr=cn uid uidNumber gidNumber homeDirectory
userPassword loginShell gecos description objectClass
4f3f7580 conn=1003 op=55 SEARCH RESULT tag=101 err=0 nentries=0 text=
4f3f7580 conn=1003 op=56 SEARCH RESULT tag=101 err=2 nentries=0 text=invalid
deref"

The old entry remains in the cache and is returned as the current value.