merge revision(s) 42890: [Backport #8878]
* tool/rbinstall.rb (Gem::Specification#initialize): default date to RUBY_RELEASE_DATE. [ruby-core:57072] [Bug #8878] * tool/rbinstall.rb (Gem::Specification#to_ruby): add date.
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@42946 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 42890: [Backport #8878]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@42946 b2dd03c8-39d4-4d8f-98ff-823fe69b080e