Fix typo in librustc_trans/collector.rs

[jtxx000]

No description provided.

[rust-highfive]

Thanks for the pull request, and welcome! The Rust team is excited to review your changes, and you should hear from @eddyb (or someone else) soon.

If any changes to this PR are deemed necessary, please add them as extra commits. This ensures that the reviewer can see what has changed since they last reviewed the code. Due to the way GitHub handles out-of-date commits, this should also make it reasonably obvious what issues have or haven't been addressed. Large or tricky changes may require several passes of review and changes.

Please see the contribution instructions for more information.

[eddyb]

@bors r+

[bors]

📌 Commit 7e73884 has been approved by eddyb

[bors]

⌛ Testing commit 7e73884 with merge 4be49e1...

[bors]

☀️ Test successful - status-appveyor, status-travis
Approved by: eddyb
Pushing 4be49e1 to master...