bump: vendored feature uses v4.1.1

[Orycterope]

Yara just released v4.1.1, which is just a bugfix release containing a fix i'm interested in.

This PR simply bumps the submodule to the newest version, and updates the travis jobs to manually build this version too.

I haven't updated the bundled bindings files, since this is just a bugfix release and there's no change to the api (or at least I hope so, and travis will confirm it).

[Hugal31]

Thanks for your PR.

There is just on thing that bother me: you included the patch version number in the feature flag name on purpose, in #22, because you said "because yara does not use semantic versioning, and patch updates sometimes still break compatibility". So we should update the bundled headers anyway.

[Orycterope]

You're right. Since the bindings are completely identical, i've just renamed the files, and I've updated the name of the feature to bundled-4_1_1