perf tools: Align perf version output to other build messages

Before:

CC util/pmu.o
CC util/parse-events.o
PERF_VERSION = 3.12.rc4.g1b30c
CC util/parse-events-flex.o
GEN perf-archive

After:

CC util/pmu.o
CC util/parse-events.o
PERF_VERSION = 3.12.rc4.g1b30c
CC util/parse-events-flex.o
GEN perf-archive

Signed-off-by: Ingo Molnar <[e-mail]>
Cc: David Ahern <[e-mail]>
Cc: Jiri Olsa <[e-mail]>
Cc: Namhyung Kim <[e-mail]>
Cc: Peter Zijlstra <[e-mail]>
Link: http://lkml.kernel.org/r/[e-mail]
Signed-off-by: Arnaldo Carvalho de Melo <[e-mail]>

tools/perf/util/PERF-VERSION-GEN

···
 	VC=unset
 fi
 test "$VN" = "$VC" || {
-	echo >&2 "PERF_VERSION = $VN"
+	echo >&2 "  PERF_VERSION = $VN"
 	echo "#define PERF_VERSION \"$VN\"" >$GVF
 }