remove from any shelf in all books shelf view

- fixes removing book from 'all books' shelf erroring
- remove from any shelf item is on when in 'all books'

bookwyrm/templates/snippets/shelf_selector.html

@@ -53,15 +53,30 @@
 {% endwith %}
 {% endif %}
 {% endfor %}
+
+{% if shelf.identifier == 'all' %}
+{% for shelved_in in book.shelves.all %}
+<li class="navbar-divider m-0" role="separator" ></li>
+<li role="menuitem" class="dropdown-item p-0">
+    <form name="shelve" action="/unshelve/" method="post">
+        {% csrf_token %}
+        <input type="hidden" name="book" value="{{ book.id }}">
+        <input type="hidden" name="shelf" value="{{ shelved_in.id }}">
+        <button class="button is-fullwidth is-small is-radiusless is-danger is-light" type="submit">{% trans "Remove from" %} {{ shelved_in.name }}</button>
+    </form>
+</li>
+{% endfor %}
+{% else %}
 <li class="navbar-divider" role="separator" ></li>
 <li role="menuitem" class="dropdown-item p-0">
     <form name="shelve" action="/unshelve/" method="post">
         {% csrf_token %}
         <input type="hidden" name="book" value="{{ book.id }}">
-        <input type="hidden" name="shelf" value="{{ current.id }}">
+        <input type="hidden" name="shelf" value="{{ shelf.id }}">
-        <button class="button is-fullwidth is-small is-radiusless is-danger is-light" type="submit">{% trans "Remove" %}</button>
+        <button class="button is-fullwidth is-small is-radiusless is-danger is-light" type="submit">{% trans "Remove from" %} {{ shelf.name }}</button>
     </form>
 </li>
+{% endif %}
 
 {% include 'snippets/reading_modals/want_to_read_modal.html' with book=active_shelf.book controls_text="want_to_read" controls_uid=uuid move_from=current.id %}