diff: use hashmap_entry_init on moved_entry.ent

Otherwise, the hashmap_entry.next field appears to remain
uninitialized, which can lead to problems when
add_lines_to_move_detection calls hashmap_add.

I found this through manual inspection when converting
hashmap_add callers to take "struct hashmap_entry *".

Signed-off-by: Eric Wong <e@80x24.org>
Reviewed-by: Derrick Stolee <stolee@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>

diff.c

@@ -964,8 +964,9 @@ static struct moved_entry *prepare_entry(struct diff_options *o,
 	struct moved_entry *ret = xmalloc(sizeof(*ret));
 	struct emitted_diff_symbol *l = &o->emitted_symbols->buf[line_no];
 	unsigned flags = o->color_moved_ws_handling & XDF_WHITESPACE_FLAGS;
+	unsigned int hash = xdiff_hash_string(l->line, l->len, flags);
 
-	ret->ent.hash = xdiff_hash_string(l->line, l->len, flags);
+	hashmap_entry_init(&ret->ent, hash);
 	ret->es = l;
 	ret->next_line = NULL;