perf tools: Move cmd_version() to builtin-version.c

Move cmd_version() to its own file so that help.c can be moved to a
library.

Signed-off-by: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Link: http://lkml.kernel.org/r/e908b1b68f20ab6d8d33941d5571c23110622e60.1449548395.git.jpoimboe@redhat.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/Build b/tools/perf/Build
index 2c7aaf2..2a41217 100644
--- a/tools/perf/Build
+++ b/tools/perf/Build
@@ -20,6 +20,7 @@
 perf-y += builtin-inject.o
 perf-y += builtin-mem.o
 perf-y += builtin-data.o
+perf-y += builtin-version.o
 
 perf-$(CONFIG_AUDIT) += builtin-trace.o
 perf-$(CONFIG_LIBELF) += builtin-probe.o