TextEditor: Avoid removing text marks that were not added to hash

TextMarks with empty file names are not added, no reason to remove them.

Change-Id: I8647deaa1136294d2f7c3c63337d967afea675c2
Reviewed-by: David Schulz <david.schulz@qt.io>

src/plugins/texteditor/textmark.cpp

@@ -88,7 +88,8 @@ TextMark::TextMark(const QString &fileName, int lineNumber, Id category, double
 
 TextMark::~TextMark()
 {
-    TextMarkRegistry::remove(this);
+    if (!m_fileName.isEmpty())
+        TextMarkRegistry::remove(this);
     if (m_baseTextDocument)
         m_baseTextDocument->removeMark(this);
     m_baseTextDocument = 0;