ssl: avoid reaching into BoringSSL (#3070)
ssl: avoid reaching into BoringSSL (#3070)

Rather than reaching into not_resumable, there's the
SSL_SESSION_is_resumable API. (This is so a future revision of BoringSSL
can hide the SSL_SESSION struct and make it C++.)

Signed-off-by: David Benjamin <348b1b6801801c3d890b2e1589a8e36441d09fdc@google.com>
lyft/envoy,lyft/envoy,lizan/envoy,dnoe/envoy,istio/envoy,istio/envoy,lizan/envoy,eklitzke/envoy,eklitzke/envoy,istio/envoy,lizan/envoy,lyft/envoy,jrajahalme/envoy,jrajahalme/envoy,dnoe/envoy,envoyproxy/envoy-wasm,istio/envoy,envoyproxy/envoy-wasm,jrajahalme/envoy,eklitzke/envoy,envoyproxy/envoy,lyft/envoy,envoyproxy/envoy,lizan/envoy,envoyproxy/envoy-wasm,envoyproxy/envoy,eklitzke/envoy,sebrandon1/envoy,istio/envoy,lyft/envoy,envoyproxy/envoy,envoyproxy/envoy-wasm,sebrandon1/envoy,envoyproxy/envoy,eklitzke/envoy,lyft/envoy,sebrandon1/envoy,envoyproxy/envoy,envoyproxy/envoy,envoyproxy/envoy,jrajahalme/envoy,envoyproxy/envoy-wasm,lizan/envoy,lizan/envoy,jrajahalme/envoy,envoyproxy/envoy,dnoe/envoy,sebrandon1/envoy,envoyproxy/envoy-wasm,dnoe/envoy,istio/envoy,envoyproxy/envoy,envoyproxy/envoy,eklitzke/envoy,envoyproxy/envoy,jrajahalme/envoy,sebrandon1/envoy,istio/envoy,envoyproxy/envoy-wasm,dnoe/envoy