[infer][PR] Fix opam remove error
[infer][PR] Fix opam remove error

Summary:
Please see [CONTRIBUTING.md](./CONTRIBUTING.md) for how to set up your development environment and run tests.

https://github.com/facebook/infer/pull/1181

https://github.com/facebook/infer/issues/1240
Pull Request resolved: https://github.com/facebook/infer/pull/1241

Reviewed By: dulmarod

Differential Revision: D20766779

Pulled By: jvillard

fbshipit-source-id: 8ed01b230

facebook/infer,facebook/infer,jvillard/infer,jvillard/infer,jvillard/infer,facebook/infer,facebook/infer,facebook/infer,facebook/infer,jvillard/infer,jvillard/infer,jvillard/infer,jvillard/infer,facebook/infer