common.mk: timestamp for update-unicode
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48117 b2dd03c8-39d4-4d8f-98ff-823fe69b080e
common.mk: timestamp for update-unicode
files twice at one build. [Bug #10415]
git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48117 b2dd03c8-39d4-4d8f-98ff-823fe69b080e