Fix integer overflow in hash_old

[MariuszCwikla]

In #216 X509Name.hash was fixed and old implementation renamed to hash_old
However I discovered that old method still wasn't working correclty due to integer overflow:

ruby -e "require 'openssl'; p OpenSSL::X509::Name.new([['CN', 'foo'], ['DC', 'bar']]).hash_old"
3294068023

jruby -e "require 'openssl'; p OpenSSL::X509::Name.new([['CN', 'foo'], ['DC', 'bar']]).hash_old"
-1000899273

Ruby is using unsinged int for this calculation. In JRuby changing int to long solves the issue.

[headius]

@MariuszCwikla The PR looks fine but the test should either be added to spec/ruby or test/jruby. The tests under test/mri are copied from CRuby and we do not edit them in our repo.

Thanks for the PR!

[MariuszCwikla]

@headius thanks for hints but it seems that jruby-openssl is not consistent jruby repo.
MRI tests even for openssl module are in jruby repo (but disabled).
And there is no test/jruby under jruby-openssl, only test/ruby