libdb: simplify buildout.cfg.

component/libdb/buildout.cfg

 [buildout]
 parts = libdb
 
-[libdb-hooks-download]
-url = ${:_profile_base_location_}/${:filename}
-md5sum = acb3bfb990a48381176c1e8f74130e30
-recipe = hexagonit.recipe.download
-download-only=true
-filename = libdb-hooks.py
-
 [libdb]
 recipe = slapos.recipe.cmmi
 url = http://download.oracle.com/berkeley-db/db-4.5.20.tar.gz
 md5sum = b0f1c777708cb8e9d37fb47e7ed3312d
-pre-configure-hook = ${libdb-hooks-download:location}/${libdb-hooks-download:filename}:pre_configure_hook
-configure-command = ../dist/configure
+configure-command = cd build_unix && ../dist/configure
 configure-options =
   --disable-static
   --prefix=${buildout:parts-directory}/${:_buildout_section_name_}
+make-binary = cd build_unix && make

component/libdb/libdb-hooks.py

-import os
-def pre_configure_hook(options, buildout):
-  os.chdir('build_unix')