Make '--decorate' set an explicit 'show_decorations' flag

We will want to add decorations without necessarily showing them, so add
an explicit revisions info flag as to whether we're showing decorations
or not.

Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin-log.c b/builtin-log.c
index 176cbce..82ea07b 100644
--- a/builtin-log.c
+++ b/builtin-log.c
@@ -28,7 +28,6 @@
 		      struct rev_info *rev)
 {
 	int i;
-	int decorate = 0;
 
 	rev->abbrev = DEFAULT_ABBREV;
 	rev->commit_format = CMIT_FMT_DEFAULT;
@@ -55,7 +54,7 @@
 		const char *arg = argv[i];
 		if (!strcmp(arg, "--decorate")) {
 			load_ref_decorations();
-			decorate = 1;
+			rev->show_decorations = 1;
 		} else if (!strcmp(arg, "--source")) {
 			rev->show_source = 1;
 		} else