[close #127] Fix LPXC Deadlock Error

LPXC can experience a deadlock error reported in #127 it was fixed in this commit:
https://github.com/ryandotsmith/lpxc/commit/1f0bd9c31324cac109a94f70589f62652b0146a3

We are vendoring those changes in in this commit
Merge pull request #128 from heroku/schneems/lpxc-fix

[close #127] Fix LPXC Deadlock Error