driver.c: Revert "Update message"

This reverts commit 85841d0bbdb10e73373032ba4f2cd88a4ec9f80d.

Some scripts unfortunately depend on the verbage "Mono JIT compiler"
in the "mono --version" message. While this was never a blessed
or supported way of getting the version (use pkg-config) of Mono,
nonetheless this breaks some important stuff. We can use the better
message in the (somewhat distant) future.