Not Support For Ruby 2.4.0

[zhangjiha]

When I run R509::Cert::Extensions::BasicConstraints.new(ca: false), raise Error
NoMethodError: undefined method value' for nil:NilClass from /Users/xxxxx/.rvm/gems/ruby-2.4.0/gems/r509-1.0.1/lib/r509/asn1.rb:20:in get_extension_payload'
from /Users/xxxxxx/.rvm/gems/ruby-2.4.0/gems/r509-1.0.1/lib/r509/cert/extensions/basic_constraints.rb:67:in parse_extension' from /Users/xxxxxx/.rvm/gems/ruby-2.4.0/gems/r509-1.0.1/lib/r509/cert/extensions/basic_constraints.rb:33:in initialize'
from (irb):14:in new' from (irb):14 from /Users/xxxxxx/.rvm/rubies/ruby-2.4.0/bin/irb:11:in

'

[zhangjiha]

I change
OpenSSL::ASN1.decode(asn.entries.last.value).value
to
OpenSSL::ASN1.decode(asn.value.last.value).value
in asn1.rb, and it is OK.
I think the reason is that ruby 2.4.0 is not support entries by value instance value

[reaperhulk]

If you can write a patch to support both Ruby 2.4 and older Ruby I will review it. Thank you for investigating.