Remove hhvm from Travis build
Remove hhvm from Travis build

As it fails initializing the project.

See https://travis-ci.org/openl10n/openl10n/jobs/38711799

Nedeas/openl10n,openl10n/openl10n,openl10n/openl10n,Nedeas/openl10n,rmoorman/openl10n,joelwurtz/openl10n,openl10n/openl10n,joelwurtz/openl10n,rmoorman/openl10n,joelwurtz/openl10n,Nedeas/openl10n,openl10n/openl10n,joelwurtz/openl10n,Nedeas/openl10n,rmoorman/openl10n,rmoorman/openl10n