LU-6142 tests: Remove file rmdirmany.c

LU-6142 tests: Remove file rmdirmany.c

This patch removes file lustre/tests/rmdirmany.c
This file currently is not used at all by any
tests or binary.

Signed-off-by: Arshad Hussain <arshad.super@gmail.com>
Change-Id: I3bd39abefb49855d70eed3be57f8e80e2439776d
Reviewed-on: https://review.whamcloud.com/36439
Tested-by: jenkins <devops@whamcloud.com>
Reviewed-by: Shaun Tancheff <stancheff@cray.com>
Reviewed-by: Ben Evans <bevans@cray.com>
Reviewed-by: Petros Koutoupis <pkoutoupis@cray.com>
Reviewed-by: Andreas Dilger <adilger@whamcloud.com>
Tested-by: Maloo <maloo@whamcloud.com>
Reviewed-by: James Simmons <jsimmons@infradead.org>