Changed CRYPT_BLOWFISH to 1 because apparently it is available

Summary: CRYPT_BLOWFISH is set to 0 in HHVM. PHP's documentation states that it is set to 1 where blowfish is available in `crypt`.

Blowfish support is available in HHVM since 4a23fdc0dc804c9a5fa8bc84f9016c1d44597afb so the constant should be set to 1.

Fixes #3274

Closes https://github.com/facebook/hhvm/pull/3284

Reviewed By: @JoelMarcey

Differential Revision: D1460377

Pulled By: svcscm