OpenGL2: Use ri.Error instead of Com_Error in tr_vbo.c

Com_Error is a wrapper for ri.Error. Use it directly.

code/renderergl2/tr_vbo.c

@@ -115,7 +115,7 @@ vao_t *R_CreateVao(const char *name, byte *vertexes, int vertexesSize, byte *ind
 			break;
 
 		default:
-			Com_Error(ERR_FATAL, "bad vaoUsage_t given: %i", usage);
+			ri.Error(ERR_FATAL, "bad vaoUsage_t given: %i", usage);
 			return NULL;
 	}