Fix build

was failing with:

Error: '/bin/bash' is an invalid shebang you need USES=shebangfix for 'lib/ruby/gems/2.4/gems/passenger-5.1.12/dev/ci/tests/debian/run'
Error: '/bin/bash' is an invalid shebang you need USES=shebangfix for 'lib/ruby/gems/2.4/gems/passenger-5.1.12/dev/ci/tests/rpm/run'
Error: '/usr/local/bin/python2' is an invalid shebang you need USES=shebangfix for 'lib/ruby/gems/2.4/gems/passenger-5.1.12/src/cxx_supportlib/vendor-copy/libuv/gyp_uv.py'

Approved by: portmgr@ (blanket approval)