Disable DBUS support for zbar as:

- it's not used in a SlapOS system (seems only used for webcam support)
- it breaks the concept of SlapOs containerization
- finally it tries to create a DBUS file in /etc/dbus-1/system.d/ which is NOT
  allowed (rightfully) for a slapsoft user

component/zbar/buildout.cfg

@@ -25,6 +25,7 @@ configure-options =
   --without-python 
   --without-x
   --without-jpg
+  --without-dbus
 environment =
   PATH=${autoconf:location}/bin:${automake:location}/bin:${gettext:location}/bin:${libtool:location}/bin:${m4:location}/bin:${bzip2:location}/bin:%(PATH)s
   CFLAGS=