Use bitflags 0.5 in the breaks branch

[saurvs]

Part of servo/servo#10077.

[sfackler]

Doesn't appear to compile: https://travis-ci.org/sfackler/rust-openssl/builds/118684997

[gkoz]

Bitflags 0.5 makes everything private by default. You can't just bump the version, you need to change flags Foo: ... to pub flags Foo: ....

[saurvs]

I added pub but it doesn't fix it because it the ffi_extras and ffi namespaces aren't being resolved for some reason. It works fine if the constants from those modules are replaced with literals. Any idea why this is happening?

[sfackler]

Covered by #385