vcs.rb: --add-author-from option

From: Nobuyoshi Nakada <nobu@ruby-lang.org>

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@61312 b2dd03c8-39d4-4d8f-98ff-823fe69b080e

tool/vcs.rb

@@ -469,7 +469,7 @@ class VCS
 
     def commit
       rev = cmd_read(%W"#{COMMAND} svn info"+[STDERR=>[:child, :out]])[/^Last Changed Rev: (\d+)/, 1]
-      ret = system(COMMAND, "svn", "dcommit")
+      ret = system(COMMAND, "svn", "dcommit", "--add-author-from")
       if ret and rev
         old = [cmd_read(%W"#{COMMAND} log -1 --format=%H").chomp]
         old << cmd_read(%W"#{COMMAND} svn reset -r#{rev}")[/^r#{rev} = (\h+)/, 1]