perf tools: Don't check configuration on make clean

perf tools: Don't check configuration on make clean

Current perf build process checks various system configuration on
invocation to make.  But this is not needed just for cleaning.

To do that, move some of python related variables out of conditional
since 'clean' target needs them.  Normal path should not be affected by
this.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1352867990-658-1-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>