openssl: don't use old BORINGSSL_YYYYMM macros #1979
Those were temporary things we'd add and remove for our own convenience
Those were temporary things we'd add and remove for our own convenience long ago. The last few stayed around for too long as an oversight but have since been removed. These days we have a running BORINGSSL_API_VERSION counter which is bumped when we find it convenient, but 2015-11-19 was quite some time ago, so just check OPENSSL_IS_BORINGSSL.