perf list: Avoid confusion of perf output and the next command prompt

Distinguish the output of 'perf list --list-opts' or 'perf --list-cmds'
with the next command prompt, which also happens in other cases (e.g.
record, report ...).

Example:

Before this patch:

 $perf list --list-opts
 --raw-dump $          <-- the output and the next command prompt are at
                           the same line

After this patch:

 $perf list --list-opts
 --raw-dump
 $                     <-- the new line
Signed-off-by: Yunlong Song <yunlong.song@huawei.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Wang Nan <wangnan0@huawei.com>
Link: http://lkml.kernel.org/r/1425032491-20224-6-git-send-email-yunlong.song@huawei.comSigned-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/perf.c

@@ -223,6 +223,7 @@ static int handle_options(const char ***argv, int *argc, int *envchanged)
 				struct cmd_struct *p = commands+i;
 				printf("%s ", p->cmd);
 			}
+			putchar('\n');
 			exit(0);
 		} else if (!strcmp(cmd, "--debug")) {
 			if (*argc < 2) {

tools/perf/util/parse-options.c

@@ -508,12 +508,14 @@ int parse_options_subcommand(int argc, const char **argv, const struct option *o
 			printf("--%s ", options->long_name);
 			options++;
 		}
+		putchar('\n');
 		exit(130);
 	case PARSE_OPT_LIST_SUBCMDS:
 		if (subcommands) {
 			for (int i = 0; subcommands[i]; i++)
 				printf("%s ", subcommands[i]);
 		}
+		putchar('\n');
 		exit(130);
 	default: /* PARSE_OPT_UNKNOWN */
 		if (ctx.argv[0][1] == '-') {