perf diff: Fix usage array, it must end with a NULL entry

Fixing this:

 [acme@doppio linux-2.6-tip]$ perf diff --hell
   Error: unknown option `hell'

  usage: perf diff [<options>] [old_file] [new_file]
 Segmentation fault
 [acme@doppio linux-2.6-tip]$

Also go over the other such arrays to check if they all were OK,
they are, but there were some minor changes to do like making
one static and renaming another to match the command it refers
to.
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Paul Mackerras <paulus@samba.org>
LKML-Reference: <1261161358-23959-1-git-send-email-acme@infradead.org>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

tools/perf/builtin-buildid-list.c

@@ -17,7 +17,7 @@
 static char const *input_name = "perf.data";
 static int force;
 
-static const char *const buildid_list_usage[] = {
+static const char * const buildid_list_usage[] = {
 	"perf buildid-list [<options>]",
 	NULL
 };

tools/perf/builtin-diff.c

@@ -189,8 +189,9 @@ out_delete:
 	return ret;
 }
 
-static const char *const diff_usage[] = {
+static const char * const diff_usage[] = {
 	"perf diff [<options>] [old_file] [new_file]",
+	NULL,
 };
 
 static const struct option options[] = {

tools/perf/builtin-report.c

@@ -294,8 +294,7 @@ setup:
 	return 0;
 }
 
-//static const char * const report_usage[] = {
-const char * const report_usage[] = {
+static const char * const report_usage[] = {
 	"perf report [<options>] <command>",
 	NULL
 };

tools/perf/builtin-trace.c

@@ -512,7 +512,7 @@ static char *get_script_path(const char *script_root, const char *suffix)
 	return path;
 }
 
-static const char * const annotate_usage[] = {
+static const char * const trace_usage[] = {
 	"perf trace [<options>] <command>",
 	NULL
 };
@@ -581,7 +581,7 @@ int cmd_trace(int argc, const char **argv, const char *prefix __used)
 
 	setup_scripting();
 
-	argc = parse_options(argc, argv, options, annotate_usage,
+	argc = parse_options(argc, argv, options, trace_usage,
 			     PARSE_OPT_STOP_AT_NON_OPTION);
 
 	if (symbol__init() < 0)