perf_counter tools: Remove zlib dependency

The zlib devel libraries may not be installed and since we aren't
using zlib we may as well remove it.

Signed-off-by: Anton Blanchard <anton@samba.org>
Cc: a.p.zijlstra@chello.nl
Cc: paulus@samba.org
LKML-Reference: <20090630230140.802078956@samba.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>