Fixed Coverity reported issue, in this case it's a unused member variable so could just be deleted.

CID 11687: Uninitialized pointer field (UNINIT_CTOR)
Non-static class member _glBeginEndAdapter is not initialized in this constructor nor in any functions that it calls.

src/osg/ArrayDispatchers.cpp

@@ -163,7 +163,6 @@ class TemplateTargetAttributeDispatch : public AttributeDispatch
             _functionPtr(_target, &(_array[pos * _stride]));
         }
 
-        GLBeginEndAdapter*      _glBeginEndAdapter;
         F                       _functionPtr;
         I                       _target;
         unsigned int            _stride;