perf probe: Check hyphen only argument

Check hyphen only command argument, because perf-probe doesn't
support event recording feature yet.

e.g.

 # perf probe -
  Error: '-' is not supported.
Signed-off-by: Masami Hiramatsu <mhiramat@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Jim Keniston <jkenisto@us.ibm.com>
Cc: Ananth N Mavinakayanahalli <ananth@in.ibm.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Frank Ch. Eigler <fche@redhat.com>
Cc: Jason Baron <jbaron@redhat.com>
Cc: K.Prasad <prasad@linux.vnet.ibm.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Srikar Dronamraju <srikar@linux.vnet.ibm.com>
Cc: systemtap <systemtap@sources.redhat.com>
Cc: DLE <dle-develop@lists.sourceforge.net>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
LKML-Reference: <20091215153128.17436.9266.stgit@dhcp-100-2-132.bos.redhat.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-probe.c

@@ -205,8 +205,13 @@ int cmd_probe(int argc, const char **argv, const char *prefix __used)
 
 	argc = parse_options(argc, argv, options, probe_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
-	if (argc > 0)
+	if (argc > 0) {
+		if (strcmp(argv[0], "-") == 0) {
+			pr_warning("  Error: '-' is not supported.\n");
+			usage_with_options(probe_usage, options);
+		}
 		parse_probe_event_argv(argc, argv);
+	}
 
 	if ((!session.nr_probe && !session.dellist && !session.list_events))
 		usage_with_options(probe_usage, options);