Kit options widget: Update the "unique display name" warning on removal

If we had two kits with the same name and removed one of them, the
remaining one would still show the warning about a non-unique display
name. This is fixed now.

Change-Id: I99e379c4885eb19021ee835d7fb9332f1795623c
Reviewed-by: Christian Stenger <christian.stenger@qt.io>

src/plugins/projectexplorer/kitmodel.cpp

@@ -226,6 +226,7 @@ void KitModel::markForRemoval(Kit *k)
         delete node;
     else
         m_toRemoveList.append(node);
+    validateKitNames();
 }
 
 Kit *KitModel::markForAddition(Kit *baseKit)
@@ -321,6 +322,7 @@ void KitModel::removeKit(Kit *k)
             if (m_defaultNode == n)
                 m_defaultNode = nullptr;
             delete n;
+            validateKitNames();
             return;
         }
     }