Motivation
SSL unit tests started failing for me (RHEL 7.6) after #9162. It looks
like the intention was to prevent disable use of the
io.netty.handler.ssl.openssl.useKeyManagerFactory property when using
BoringSSL, but it now gets set to false in that case rather than the
prior/non-BoringSSL default of true.
Modification
Set useKeyManagerFactory to true rather than false in BoringSSL case
during static init of OpenSSl class.
Result
Tests pass again.