fails

The bug was introduced with the push of the fix for bug#20953: after
the error on view creation we never reset the error state, so some
valid statements would give the same error after that.

The solution is to properly reset the error state.


mysql-test/r/view.result:
  Add result for bug#25897: Some queries are no longer possible after
  a CREATE VIEW fails.
mysql-test/t/view.test:
  Add test case for bug#25897: Some queries are no longer possible after
  a CREATE VIEW fails.
sql/sql_lex.cc:
  Add st_parsing_options::reset() method, call it from lex_start().
sql/sql_lex.h:
  Add st_parsing_options::reset() method, call it from constructor.