names include backticks or blank

Problem: mysqlcheck doesn't escape backtick characters in the table names.

Fix: escape them.


client/mysqlcheck.c:
  Fix for bug #30654: mysqlcheck fails during upgrade of tables whose 
  names include backticks or blank
    - escape backtick characters in the table names.
mysql-test/r/mysqlcheck.result:
  Fix for bug #30654: mysqlcheck fails during upgrade of tables whose 
  names include backticks or blank
    - test result.
mysql-test/t/mysqlcheck.test:
  Fix for bug #30654: mysqlcheck fails during upgrade of tables whose 
  names include backticks or blank
    - test case.