vcs.rb: no ext/date in vcs.rb

* tool/vcs.rb (VCS::GIT#export_changelog): do not require date
  extension library so that miniruby can run.
  [ruby-core:78641] [Bug #13032]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@57077 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/vcs.rb

@@ -1,6 +1,5 @@
 # vcs
 require 'fileutils'
-require 'time'
 
 # This library is used by several other tools/ scripts to detect the current
 # VCS in use (e.g. SVN, Git) or to interact with that VCS.
@@ -446,7 +445,9 @@ class VCS
             s.sub!(/^git-svn-id: .*@(\d+) .*\n+\z/, '')
             rev = $1
             s.gsub!(/^ {8}/, '') if /^(?! {8}|$)/ !~ s
-            date = Time.strptime(time, "%Y-%m-%d %T %z").strftime("%a, %d %b %y")
+            if /\A(\d+)-(\d+)-(\d+)/ =~ time
+              date = Time.new($1.to_i, $2.to_i, $3.to_i).strftime("%a, %d %b %Y")
+            end
             w.puts "r#{rev} | #{author} | #{time} (#{date}) | #{s.count("\n")} lines\n\n"
             w.puts s, sep
           end