remote: fix status with branch...rebase=preserve

Commit 66713ef (pull: allow pull to preserve merges when rebasing)
didn't include an update so 'git remote status' parses branch.<name>.rebase=preserve
correctly, let's do that.

Signed-off-by: Felipe Contreras <felipe.contreras@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin/remote.c

@@ -309,8 +309,13 @@ static int config_read_branches(const char *key, const char *value, void *cb)
 				space = strchr(value, ' ');
 			}
 			string_list_append(&info->merge, xstrdup(value));
-		} else
+		} else {
-			info->rebase = git_config_bool(orig_key, value);
+			int v = git_config_maybe_bool(orig_key, value);
+			if (v >= 0)
+				info->rebase = v;
+			else if (!strcmp(value, "preserve"))
+				info->rebase = 1;
+		}
 	}
 	return 0;
 }