Unifies mysql and mysql2 casting of booleans

Using the mysql2 adapter, boolean values were sometimes being incorrectly cast
to 't' or 'f'. This changes the cast to match the mysql adapter behavior, ie 1 and 0.
Merge pull request #11120 from awilliams/ar_mysql2_boolean_quoting

Fixes AR mysql2 adapter incorrectly casting boolean values
Move initializing process for query cache to ActiveRecord::ConnectionAdapters::QueryCache module.
Merge pull request #11435 from kennyj/move_to_query_cache

Move initializing process for @query_cache to QueryCache module.
Fixed USAGE file for generator [ci skip]
Merge pull request #11458 from arunagw/fix_usage_file

Fixed USAGE file for generator [ci skip]