Bug#17371: Unable to dump a schema with invalid views

'show create' works even on views that are short of a base-table (this
throw a warning though, like you would expect). Unfortunately, this is
not what mysqldump uses; it creates stand-in tables and hence requests
'show fields' on the view which fails with missing base-tables.  The
--force option prevents the dump from stopping at this point; furthermore
this patch dumps a comment showing create for the offending view for
better diagnostics. This solution was confirmed by submitter as solving
their/clients' problem. Problem might become non-issue once mysqldump no
longer creates stand-in tables.

mysql-test/t/mysqldump.test

@@ -1143,3 +1143,16 @@ show create procedure p;
 drop function f;
 drop procedure p;
 
+#
+# Bug #17371 Unable to dump a schema with invalid views
+#
+#
+create table t1 ( id serial );
+create view v1 as select * from t1;
+drop table t1;
+# mysqldump gets 1356 from server, but gives us 2
+--echo mysqldump {
+--error 2
+--exec $MYSQL_DUMP --force -N --compact --skip-comments test
+--echo } mysqldump
+drop view v1;