Text Editor: Fix handling of snippet parameter with no name

Problem was that typing into overlay selection of the snippet
parameter with no name ended the snippet editing. For example,
"do {$$} while ($confition$);" was unusable.

Change-Id: Ife0e68340de328a3492e242ce861f7c9dd225d7e
Reviewed-by: Leandro Melo <leandro.melo@nokia.com>

src/plugins/texteditor/texteditoroverlay.cpp

@@ -95,9 +95,7 @@ void TextEditorOverlay::addOverlaySelection(int begin, int end,
     selection.m_cursor_end = QTextCursor(document->docHandle(), end);
 
     if (overlaySelectionFlags & ExpandBegin) {
-        if (begin > 0 && begin < end) { // not empty
-            selection.m_cursor_begin.setKeepPositionOnInsert(true);
-        }
+        selection.m_cursor_begin.setKeepPositionOnInsert(true);
     }
 
     if (overlaySelectionFlags & LockSize)