perf hists: Free branch_info when freeing hist_entry

perf hists: Free branch_info when freeing hist_entry

Those data should be free along with the associated hist_entry,
otherwise it'll be leaked.

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1352273234-28912-7-git-send-email-namhyung@kernel.org
[ committer note: mem_info is not yet in perf/core, free just branch_info ]
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>