Remove references to inexisting enums in Q_ENUMS

moc currently silently ignores them, but I have a version which display
a warning.

Change-Id: I9a239cb7e99d40a57a013fb66357c4a6426d6e8b
Reviewed-by: Giuseppe D'Angelo <giuseppe.dangelo@kdab.com>
Reviewed-by: Stephen Kelly <stephen.kelly@kdab.com>

src/corelib/itemmodels/qabstractitemmodel.h

@@ -154,7 +154,7 @@ template <class Key, class T> class QMap;
 class Q_CORE_EXPORT QAbstractItemModel : public QObject
 {
     Q_OBJECT
-    Q_ENUMS(LayoutChangeHints)
+    Q_ENUMS(LayoutChangeHint)
 
     friend class QPersistentModelIndexData;
     friend class QAbstractItemViewPrivate;

src/widgets/kernel/qformlayout.h

@@ -52,7 +52,7 @@ class QFormLayoutPrivate;
 class Q_WIDGETS_EXPORT QFormLayout : public QLayout
 {
     Q_OBJECT
-    Q_ENUMS(FormStyle FieldGrowthPolicy RowWrapPolicy ItemRole)
+    Q_ENUMS(FieldGrowthPolicy RowWrapPolicy ItemRole)
     Q_DECLARE_PRIVATE(QFormLayout)
     Q_PROPERTY(FieldGrowthPolicy fieldGrowthPolicy READ fieldGrowthPolicy WRITE setFieldGrowthPolicy RESET resetFieldGrowthPolicy)
     Q_PROPERTY(RowWrapPolicy rowWrapPolicy READ rowWrapPolicy WRITE setRowWrapPolicy RESET resetRowWrapPolicy)

src/widgets/widgets/qfontcombobox.h

@@ -59,7 +59,6 @@ class Q_WIDGETS_EXPORT QFontComboBox : public QComboBox
     Q_PROPERTY(QFontDatabase::WritingSystem writingSystem READ writingSystem WRITE setWritingSystem)
     Q_PROPERTY(FontFilters fontFilters READ fontFilters WRITE setFontFilters)
     Q_PROPERTY(QFont currentFont READ currentFont WRITE setCurrentFont NOTIFY currentFontChanged)
-    Q_ENUMS(FontSelection)
 
 public:
     explicit QFontComboBox(QWidget *parent = 0);