Restore compatibility with OpenSSL

During review, I asked Paul to change the call to invalidate the
encoding to use the newer BoringSSL functions. However, OpenSSL doesn't
have these functions so it broke the build with OpenSSL. Restore this
line to Paul's previous patchset to keep OpenSSL working.

Change-Id: I2fe43073db78a783c585c44b186afa634493bf91
1 file changed