Log Message:
Don't enable "readline" option default if RUBY_VER is prior to 193.

Ruby 1.9.3 changes its license and solve the problem with GPL3 of readline
license.  But Ruby 1.9.2/1.8.7 dosen't solve this problem.

If you want to use ruby-readline with GNU readline on ruby18 or ruby192,
please explictly set "readline" PKG_OPTION.

Fix PR pkg/41943.

Bump PKGREVISION.