grep with unmerged index

We called flush_grep() every time we saw an unmerged entry in
the index.  If we happen to find an unmerged entry before we saw
more than two paths, we incorrectly declared that the user had
too many non-paths options in front.

Signed-off-by: Junio C Hamano <gitster@pobox.com>

builtin-grep.c

@@ -343,7 +343,7 @@ static int external_grep(struct grep_opt *opt, const char **paths, int cached)
 			memcpy(name + 2, ce->name, len + 1);
 		}
 		argv[argc++] = name;
-		if (argc < MAXARGS && !ce_stage(ce))
+		if (argc < MAXARGS)
 			continue;
 		status = flush_grep(opt, argc, nr, argv, &kept);
 		if (0 < status)