Log Message:
Update to 1.27.2

Changelog:
Version 1.27.2 (2018-07-20)

Compatibility Notes

 * The borrow checker was fixed to avoid potential unsoundness when using
   match ergonomics: #52213.

Version 1.27.1 (2018-07-10)

Security Notes

 * rustdoc would execute plugins in the /tmp/rustdoc/plugins directory when
   running, which enabled executing code as some other user on a given
   machine. This release fixes that vulnerability; you can read more about
   this on the blog.

   Thank you to Red Hat for responsibily disclosing this vulnerability to us.

Compatibility Notes

 * The borrow checker was fixed to avoid an additional potential unsoundness
   when using match ergonomics: #51415, #49534.