am: ignore return value of write_file()

write_file() either returns 0 or dies, so there is no point in checking
its return value.  The callers of the wrappers write_state_text(),
write_state_count() and write_state_bool() consequently already ignore
their return values.  Stop pretending we care and make them void.

Signed-off-by: Rene Scharfe <l.s.r@web.de>
Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/am.c

@@ -183,22 +183,22 @@ static inline const char *am_path(const struct am_state *state, const char *path
 /**
  * For convenience to call write_file()
  */
-static int write_state_text(const struct am_state *state,
-			    const char *name, const char *string)
+static void write_state_text(const struct am_state *state,
+			     const char *name, const char *string)
 {
-	return write_file(am_path(state, name), "%s", string);
+	write_file(am_path(state, name), "%s", string);
 }
 
-static int write_state_count(const struct am_state *state,
-			     const char *name, int value)
+static void write_state_count(const struct am_state *state,
+			      const char *name, int value)
 {
-	return write_file(am_path(state, name), "%d", value);
+	write_file(am_path(state, name), "%d", value);
 }
 
-static int write_state_bool(const struct am_state *state,
-			    const char *name, int value)
+static void write_state_bool(const struct am_state *state,
+			     const char *name, int value)
 {
-	return write_state_text(state, name, value ? "t" : "f");
+	write_state_text(state, name, value ? "t" : "f");
 }
 
 /**