perf annotate: Fix missing number of samples for source_line_samples

The option 'show-total-period' works fine without a option '-l'.  But if
running 'perf annotate --stdio -l --show-total-period', you can see a
problem showing only zero '0' for number of samples.

Before:
    $ perf annotate --stdio -l --show-total-period
...
       0 :        400816:       push   %rbp
       0 :        400817:       mov    %rsp,%rbp
       0 :        40081a:       mov    %edi,-0x24(%rbp)
       0 :        40081d:       mov    %rsi,-0x30(%rbp)
       0 :        400821:       mov    -0x24(%rbp),%eax
       0 :        400824:       mov    -0x30(%rbp),%rdx
       0 :        400828:       mov    (%rdx),%esi
       0 :        40082a:       mov    $0x0,%edx
...

The reason is it was missed to set number of samples of
source_line_samples, so set it ordinarily.

After:
    $ perf annotate --stdio -l --show-total-period
...
       3 :        400816:       push   %rbp
       4 :        400817:       mov    %rsp,%rbp
       0 :        40081a:       mov    %edi,-0x24(%rbp)
       0 :        40081d:       mov    %rsi,-0x30(%rbp)
       1 :        400821:       mov    -0x24(%rbp),%eax
       2 :        400824:       mov    -0x30(%rbp),%rdx
       0 :        400828:       mov    (%rdx),%esi
       1 :        40082a:       mov    $0x0,%edx
...

Signed-off-by: Taeung Song <treeze.taeung@gmail.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: Martin Liska <mliska@suse.cz>
Cc: Masami Hiramatsu <mhiramat@kernel.org>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Wang Nan <wangnan0@huawei.com>
Fixes: 0c4a5bce

 ("perf annotate: Display total number of samples with --show-total-period")
Link: http://lkml.kernel.org/r/1490703125-13643-1-git-send-email-treeze.taeung@gmail.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>