builtin/blame.c: refactor commit_info_init() to COMMIT_INFO_INIT macro

Remove the commit_info_init() function addded in ea02ffa385 (mailmap:
simplify map_user() interface, 2013-01-05) and instead initialize the
"struct commit_info" with a macro.

This is the more idiomatic pattern in the codebase, and doesn't leave
us wondering when we see the *_init() function if this struct needs
more complex initialization than a macro can provide.

The get_commit_info() function is only called by the three callers
being changed here immediately after initializing the struct with the
macros, so by moving the initialization to the callers we don't need
to do it in get_commit_info() anymore.

Signed-off-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/blame.c

@@ -101,6 +101,16 @@ struct commit_info {
 	struct strbuf summary;
 };
 
+#define COMMIT_INFO_INIT { \
+	.author = STRBUF_INIT, \
+	.author_mail = STRBUF_INIT, \
+	.author_tz = STRBUF_INIT, \
+	.committer = STRBUF_INIT, \
+	.committer_mail = STRBUF_INIT, \
+	.committer_tz = STRBUF_INIT, \
+	.summary = STRBUF_INIT, \
+}
+
 /*
  * Parse author/committer line in the commit object buffer
  */
@@ -160,18 +170,6 @@ static void get_ac_line(const char *inbuf, const char *what,
 	strbuf_add(name, namebuf, namelen);
 }
 
-static void commit_info_init(struct commit_info *ci)
-{
-
-	strbuf_init(&ci->author, 0);
-	strbuf_init(&ci->author_mail, 0);
-	strbuf_init(&ci->author_tz, 0);
-	strbuf_init(&ci->committer, 0);
-	strbuf_init(&ci->committer_mail, 0);
-	strbuf_init(&ci->committer_tz, 0);
-	strbuf_init(&ci->summary, 0);
-}
-
 static void commit_info_destroy(struct commit_info *ci)
 {
 
@@ -192,8 +190,6 @@ static void get_commit_info(struct commit *commit,
 	const char *subject, *encoding;
 	const char *message;
 
-	commit_info_init(ret);
-
 	encoding = get_log_output_encoding();
 	message = logmsg_reencode(commit, NULL, encoding);
 	get_ac_line(message, "\nauthor ",
@@ -246,7 +242,7 @@ static void write_filename_info(struct blame_origin *suspect)
  */
 static int emit_one_suspect_detail(struct blame_origin *suspect, int repeat)
 {
-	struct commit_info ci;
+	struct commit_info ci = COMMIT_INFO_INIT;
 
 	if (!repeat && (suspect->commit->object.flags & METAINFO_SHOWN))
 		return 0;
@@ -440,7 +436,7 @@ static void emit_other(struct blame_scoreboard *sb, struct blame_entry *ent, int
 	int cnt;
 	const char *cp;
 	struct blame_origin *suspect = ent->suspect;
-	struct commit_info ci;
+	struct commit_info ci = COMMIT_INFO_INIT;
 	char hex[GIT_MAX_HEXSZ + 1];
 	int show_raw_time = !!(opt & OUTPUT_RAW_TIMESTAMP);
 	const char *default_color = NULL, *color = NULL, *reset = NULL;
@@ -630,7 +626,7 @@ static void find_alignment(struct blame_scoreboard *sb, int *option)
 		if (longest_file < num)
 			longest_file = num;
 		if (!(suspect->commit->object.flags & METAINFO_SHOWN)) {
-			struct commit_info ci;
+			struct commit_info ci = COMMIT_INFO_INIT;
 			suspect->commit->object.flags |= METAINFO_SHOWN;
 			get_commit_info(suspect->commit, &ci, 1);
 			if (*option & OUTPUT_SHOW_EMAIL)