reorder ALLOW_TEXTCONV option setting

Right now for the diff porcelain and the log family, we
call:

  init_revisions();
  setup_revisions();
  DIFF_OPT_SET(ALLOW_TEXTCONV);

However, that means textconv will _always_ be on, instead of
being a default that can be manipulated with
setup_revisions. Instead, we want:

  init_revisions();
  DIFF_OPT_SET(ALLOW_TEXTCONV);
  setup_revisions();

which is what this patch does.

We'll go ahead and move the callsite in wt-status, also;
even though the user can't pass any options here, it is a
cleanup that will help avoid any surprise later if the
setup_revisions line is changed.

Signed-off-by: Jeff King <peff@peff.net>
Signed-off-by: Junio C Hamano <gitster@pobox.com>
diff --git a/builtin-diff.c b/builtin-diff.c
index dddcf69..d75d69b 100644
--- a/builtin-diff.c
+++ b/builtin-diff.c
@@ -290,8 +290,9 @@
 	/* Otherwise, we are doing the usual "git" diff */
 	rev.diffopt.skip_stat_unmatch = !!diff_auto_refresh_index;
 
-	/* Default to let external be used */
+	/* Default to let external and textconv be used */
 	DIFF_OPT_SET(&rev.diffopt, ALLOW_EXTERNAL);
+	DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
 
 	if (nongit)
 		die("Not a git repository");
@@ -303,7 +304,6 @@
 	}
 
 	DIFF_OPT_SET(&rev.diffopt, RECURSIVE);
-	DIFF_OPT_SET(&rev.diffopt, ALLOW_TEXTCONV);
 
 	/*
 	 * If the user asked for our exit code then don't start a