configure.in: fix --with-ruby-version [ci skip]

* configure.in (RUBY_LIB_VERSION): Fix --with-ruby-version
  configuration option.  get rid of quoting in config.status.
* template/verconf.h.tmpl: quote RUBY_LIB_VERSION here.
  [ruby-core:66724] [Bug #10572]

git-svn-id: svn+ssh://ci.ruby-lang.org/ruby/trunk@48723 b2dd03c8-39d4-4d8f-98ff-823fe69b080e