Remove Result::isValid as it's always true

src/libtomahawk/Result.cpp

@@ -128,13 +128,6 @@ Result::deleteLater()
 }
 
 
-bool
-Result::isValid() const
-{
-    return m_track && !m_track->artist().isEmpty() && !m_track->track().isEmpty();
-}
-
-
 void
 Result::onResolverRemoved( Tomahawk::Resolver* resolver )
 {

src/libtomahawk/Result.h

@@ -72,8 +72,6 @@ public:
 
     virtual ~Result();
 
-    bool isValid() const;
-
     QVariant toVariant() const;
     QString toString() const;
     Tomahawk::query_ptr toQuery();