RE: simpler lockobj for back-bdb entry cache locking

[Jonghyuk Choi <jongchoi@us.ibm.com>]

Another combination.

No local malloc + simple lockobj + without (objectClass=referral) in
search_candidate

servers/slapd/slapd : 46.1%
libc : 20.48%
libpthread : 13.1%
vmlinux : 12.7%
libdb : 1.6%

ftp://ftp.openldap.org/incoming/profile6.txt

DirMark : around 2450 ops/sec ( lags the local malloc case by 50~100 )

So lots of libc and libpthread overhead has been reduced by the local
malloc patch.
This will pay off more as we optimize another part such as threading and
networking...