Shift/reduce conflicts for NAMES,ROLE,PASSWORD in the option_value_no_option_type grammar

The grammar rule option_value_no_option_type has shift/reduce conflicts for the following keywords:

• NAMES_SYM
• ROLE_SYM
• PASSWORD_SYM

These keywords appear in explicit grammar branches, and at the same time as a part of ident.

To fix conflicts, this grammar branch:

option_value_no_option_type:

          ident equal set_expr_or_default

          {

            if (unlikely(Lex->set_variable(&$1, $3)))

              MYSQL_YYABORT;

          }

should be change to something like this:

option_value_no_option_type:

          ident_set_usual_case equal set_expr_or_default

          {

            if (unlikely(Lex->set_variable(&$1, $3)))

              MYSQL_YYABORT;

          }

were ident_set_usual_case won't include keywords NAMES_SYM, ROLE_SYM, PASSWORD_SYM.