fix an attr/src mix-up when setting-up/binding vertex arrays

This fixes problems with incorrect material coefficients when glMaterial
is called per-vertex.

src/mesa/vbo/vbo_exec_draw.c

@@ -187,7 +187,7 @@ static void vbo_exec_bind_arrays( GLcontext *ctx )
 	 arrays[attr].BufferObj = exec->vtx.bufferobj; /* NullBufferObj */
 	 arrays[attr]._MaxElement = count; /* ??? */
 
-	 data += exec->vtx.attrsz[attr] * sizeof(GLfloat);
+	 data += exec->vtx.attrsz[src] * sizeof(GLfloat);
       }
    }
 }

src/mesa/vbo/vbo_save_draw.c

@@ -146,7 +146,7 @@ static void vbo_bind_vertex_list( GLcontext *ctx,
 	 
 	 assert(arrays[attr].BufferObj->Name);
 
-	 data += node->attrsz[attr] * sizeof(GLfloat);
+	 data += node->attrsz[src] * sizeof(GLfloat);
       }
    }
 }