[Fix #1232] make the behavior of AndOr cop configurable

Currently, the AndOr cop bans the use of keywords 'and' and 'or'
completely. This patch adds a configuration option `OnlyCheckConditionals`
which when set, restricts the AndOr cop to only conditionals.
Call `process_logical_op(node)`, and move it last so that all calls are downwards. The last 4 lines here are a duplicate.