C++: Only reindent on electric characters if indent wasn't user-changed.

This should make the indenter less strict and annoying for non-standard
indentation styles.

Reviewed-by: Roberto Raggi

src/plugins/cpptools/cppcodeformatter.h

@@ -69,6 +69,7 @@ public:
     void updateLineStateChange(const QTextBlock &block);
 
     int indentFor(const QTextBlock &block);
+    int indentForNewLineAfter(const QTextBlock &block);
 
     void setTabSize(int tabSize);