perf ui/tui: Print backtrace symbols when segfault occurs

The output will look like below.  (I added an error into ui__init() for
the test).

  $ perf report
  perf: Segmentation fault
  -------- backtrace --------
  perf[0x503781]
  /usr/lib/libc.so.6(+0x33b20)[0x7f1a14f04b20]
  perf(ui__init+0xd5)[0x503645]
  perf(setup_browser+0x97)[0x4ce4e7]
  perf(cmd_report+0xcea)[0x4392ba]
  perf[0x428493]
  perf(main+0x60a)[0x427c0a]
  /usr/lib/libc.so.6(__libc_start_main+0xf0)[0x7f1a14ef1040]
  perf[0x427d29]
  [0x0]

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Link: http://lkml.kernel.org/r/1419223455-4362-4-git-send-email-namhyung@kernel.org


Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>