bind: fix configure in case lmdb devel files are present on the host

Fix configure failure in case lmdb devel files are present on the host
by adding --without-lmdb option (reported [1] and fix tested [2],[3] by
grunpferd@netscape.net).

Fixes:

  checking for lmdb library... yes
  checking for library containing mdb_env_create... no
  configure: error: found lmdb include but not library.

[1] http://lists.busybox.net/pipermail/buildroot/2017-August/199945.html
[2] http://lists.busybox.net/pipermail/buildroot/2017-August/199963.html
[3] http://lists.busybox.net/pipermail/buildroot/2017-August/199964.html



Signed-off-by: Peter Seiderer <ps.report@gmx.net>
Signed-off-by: Arnout Vandecappelle (Essensium/Mind) <arnout@mind.be>