Update fakeReadline() to use libedit::readline() on pre 5.4 versions of php. Mitigates bug in libedit/readline.

https://answers.launchpad.net/ius/+question/198150

php53u version of php includes libedit but not readline and due to above
bug, various readline functions were not mapped thru properly.

This patch at least gives reasonable readline functionality on 5.3
versions since the above bug was fixed only in 5.4.0.