[ticket/13846] Fix softdelete feature workflow in viewtopic

Changes:
- For permanent deletion of softdeleted post, disapprove mode has been changed
to delete mode;
- If post delete and softdelete are allowed, delete button triggers softdelete
mode;
- If a user can't permanently delete posts but can restore softdeleted posts,
delete button won't be displayed for softdeleted posts.
Subsilver2 is unaffected.

PHPBB3-13846

phpBB/styles/prosilver/template/viewtopic_body.html

@@ -269,7 +269,9 @@
 			<form method="post" class="mcp_approve" action="{postrow.U_APPROVE_ACTION}">
 				<p class="post-notice deleted">
 					<strong>{L_POST_DELETED_ACTION}</strong>
-					<input class="button2" type="submit" value="{L_DELETE}" name="action[disapprove]" />
+					<!-- IF postrow.S_DELETE_PERMANENT -->
+						<input class="button2" type="submit" value="{L_DELETE}" name="action[delete]" />
+					<!-- ENDIF -->
 					<input class="button1" type="submit" value="{L_RESTORE}" name="action[restore]" />
 					<input type="hidden" name="post_id_list[]" value="{postrow.POST_ID}" />
 					{S_FORM_TOKEN}