LU-3959 build: fix make rpms for lustre-iokit

LU-3959 build: fix make rpms for lustre-iokit

With the recent merge of the lustre-iokit build
system with lustre's build system on some platforms
running make rpms from the top of the lustre tree
breaks with

make -C lustre-iokit  rpms
make[1]: Entering directory `lustre-2.4.93/lustre-iokit'
make[1]: *** No rule to make target `rpms'.  Stop.

This patch removes the offending code in the makfile
without breaking anything else.

Signed-off-by: James Simmons <uja.ornl@gmail.com>
Change-Id: I837ab1c2c383e1ca68eaadc492c3c8cf18cecb92
Reviewed-on: http://review.whamcloud.com/7771
Reviewed-by: Minh Diep <minh.diep@intel.com>
Reviewed-by: Christopher J. Morrone <chris.morrone.llnl@gmail.com>
Reviewed-by: Andreas Dilger <andreas.dilger@intel.com>
Tested-by: Hudson
Tested-by: Maloo <whamcloud.maloo@gmail.com>
Reviewed-by: Brian J. Murrell <brian.murrell@intel.com>