Revert "Merge pull request #499 from xfix/unix-invalid-unicode"
Revert "Merge pull request #499 from xfix/unix-invalid-unicode"

This reverts commit 061748e1f5ad3b556958c2d2b8badfd32edb2b81, reversing
changes made to cf3cdecf1290c8595087f354b29b2c4ff2d2b645.

jgallagher/rusqlite,jgallagher/rusqlite,jgallagher/rusqlite