diff-merges: group diff-merge flags next to each other inside 'rev_info'

The relevant flags were somewhat scattered over definition of 'struct
rev_info'. Rearrange them to group them together.

Signed-off-by: Sergey Organov <sorganov@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

revision.h

@@ -191,13 +191,14 @@ struct rev_info {
 			match_missing:1,
 			no_commit_id:1,
 			verbose_header:1,
+			always_show_header:1,
+			/* Diff-merge flags */
 			explicit_diff_merges: 1,
 			separate_merges: 1,
 			combine_merges:1,
 			combined_all_paths:1,
 			dense_combined_merges:1,
-			first_parent_merges:1,
-			always_show_header:1;
+			first_parent_merges:1;
 
 	/* Format info */
 	int		show_notes;