merge revision(s) 43609,43617: [Backport #8878] [Backport #9085]
vcs.rb: split * tool/vcs.rb: split from file2lastrev.rb. * tool/rbinstall.rb (Gem::Specification.load): obtain spec date from VCS for the case using git, RUBY_RELEASE_DATE is the last resort. probably fixes [Bug #9085].
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@43655 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
merge revision(s) 43609,43617: [Backport #8878] [Backport #9085]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/branches/ruby_2_0_0@43655 b2dd03c8-39d4-4d8f-98ff-823fe69b080e