iputils: remove comment-only Cleanspec.mk

The following:
  egrep -v '^#|^ *$' < CleanSpec.mk
was empty.

So just delete the pointless file, and thus reduce the diff versus upstream.

Test: N/A
Bug: 140825634
Signed-off-by: Maciej Żenczykowski <maze@google.com>
Change-Id: Ie6445f00ff8792ca15d85629b88147aac95ba641
1 file changed