lmbench: remove debianutils from RDEPENDS and add perl

- I don't see any evdidence that lmbench needs debianutils to run:
  debianutils provides:
    run-parts, tempfile, savelog, which, ischroot,
    add-shell, installkernel, remove-shell
  but none of them is used by lmbench scripts and I tested it work
  fine without debianutils, so remove debianutils from RDEPENDS

- Some scripts in lmbench are perl scripts, so add
  RDEPENDS on perl (no addtional perl module is needed).

Signed-off-by: Jackie Huang <jackie.huang@windriver.com>
Signed-off-by: Martin Jansa <Martin.Jansa@gmail.com>