RSpec/BeforeAll: Allow before(:all) for :delete specs

To avoid broken master #420379 (closed):

Modify the RSpec/BeforeAll cop to allow before(:all) for :delete specs.

An additional related idea:

I think the cop should allow before(:all) for :delete specs.

Does it make sense if we use another method to wrap around before_all and before(:all)? It's been very confusing to me and I keep forgetting which is which.

• before(:all) => before_all_with_delete
• before_all => before_all_with_transaction

Then we can add a cop to look at this.