Don't failsafe ActiveRecord::ConnectionTimeoutError

It hides the error and you end up with a different error anyway
as the connection is nil.

Fixes: #235

Author: djmb

lib/solid_cache/store/failsafe.rb

@@ -6,7 +6,6 @@ module Failsafe
       TRANSIENT_ACTIVE_RECORD_ERRORS = [
         ActiveRecord::AdapterTimeout,
         ActiveRecord::ConnectionNotEstablished,
-        ActiveRecord::ConnectionTimeoutError,
         ActiveRecord::Deadlocked,
         ActiveRecord::LockWaitTimeout,
         ActiveRecord::QueryCanceled,