Fix compile for Qt5.4

Introduced with f443c95dcc.

Change-Id: I6fcc2c429b90cb56a02c3c63f0788fcf0ab1df52
Reviewed-by: Thiago Macieira <thiago.macieira@intel.com>

src/plugins/coreplugin/find/basetextfind.cpp

@@ -39,7 +39,9 @@
 #include <QPlainTextEdit>
 #include <QTextCursor>
 
+#if QT_VERSION >= QT_VERSION_CHECK(5, 6, 0)
 #include <private/qtextcursor_p.h>
+#endif
 
 namespace Core {
 

src/plugins/texteditor/texteditoroverlay.cpp

@@ -37,7 +37,9 @@
 #include <QPainter>
 #include <QTextBlock>
 
+#if QT_VERSION >= QT_VERSION_CHECK(5, 6, 0)
 #include <private/qtextcursor_p.h>
+#endif
 
 using namespace TextEditor;
 using namespace TextEditor::Internal;