* data/glr.c (yyreturn): Use "Cleanup:" rather than "Error:"

in yydestruct diagnostic, since it might not be an error.
Problem reported by Joel Denny near end of
<http://lists.gnu.org/archive/html/help-bison/2005-07/msg00040.html>.
* data/lalr1cc (yyerturn): Likewise.
* data/yacc.c (yyreturn): Likewise.
* tests/calc.at (_AT_CHECK_CALC_ERROR): Adjust to the above change.

data/yacc.c

@@ -1383,11 +1383,11 @@ yyexhaustedlab:
 
 yyreturn:
   if (yychar != YYEOF && yychar != YYEMPTY)
-     yydestruct ("Error: discarding lookahead",
+     yydestruct ("Cleanup: discarding lookahead",
 		 yytoken, &yylval]b4_location_if([, &yylloc])[);
   while (yyssp != yyss)
     {
-      yydestruct ("Error: popping",
+      yydestruct ("Cleanup: popping",
 		  yystos[*yyssp], yyvsp]b4_location_if([, yylsp])[);
       YYPOPSTACK;
     }