Keep loplugin:staticmethods happy.

Change-Id: I45b576a4401d51d204007a8dde3b24617b5a17e9
diff --git a/sc/inc/formulalogger.hxx b/sc/inc/formulalogger.hxx
index 1348c63..10a0155 100644
--- a/sc/inc/formulalogger.hxx
+++ b/sc/inc/formulalogger.hxx
@@ -95,6 +95,7 @@ public:
 */
class FormulaLogger
{
    bool mbState = false; // Just to avoid loplugin:staticmethods
public:

    static FormulaLogger get()
@@ -104,13 +105,15 @@ public:

    class GroupScope
    {
        bool mbState = false; // Just to avoid loplugin:staticmethods
    public:
        void addMessage( const OUString& /*rMsg*/ ) {}
        void setCalcComplete() {}
        void addMessage( const OUString& /*rMsg*/ ) { mbState = !mbState; }
        void setCalcComplete() { mbState = !mbState; }
    };

    GroupScope enterGroup( const ScDocument& /*rDoc*/, const ScFormulaCell& /*rCell*/ )
    {
        mbState = !mbState;
        return GroupScope();
    }
};