title: netty does not detect netty-tcnative
body: <p>While looking deeper into my issue, explained atg <a href="https://stackoverflow.com/questions/44161427/grpc-with-tls-client-authentication-using-sunpkcs11-in-netty-fails">gRpc with TLS Client Authentication using SunPKCS11 in netty fails</a>, I changed the version of netty-tcnative-boringssl. The cange in my build.gradle was from</p>
  
  <pre><code>compile 'io.netty:netty-tcnative-boringssl-static:1.1.33.Fork26' 
  </code></pre>
  
  <p>to</p>
  
  <pre><code>compile 'io.netty:netty-tcnative-boringssl-static:+'
  </code></pre>
  
  <p>resulting in:</p>
  
  <blockquote>
    <p>+--- io.netty:netty-tcnative-boringssl-static:+ -> 2.0.1.Final</p>
  </blockquote>
  
  <p>I did this, because according to netty's javadoc <code>SslContextBuilder's</code> <code>keyManager(KeyManagerFactory factory)</code> method also works for OpenSSL as provider, which it does not for version 1.1.33.Fork26.</p>
  
  <p>Now, with the new version the slf4j debug output of netty tells me:</p>
  
  <blockquote>
    <p>[main] DEBUG io.netty.handler.ssl.OpenSsl - netty-tcnative not in the
    classpath; OpenSslEngine will be unavailable</p>
  </blockquote>
  
  <p>So the detection of netty-tcnative seems to fail. Debugging into 
   <code>io.netty.handler.ssl.OpenSsl</code>'s static code block,
  the detection fails, because </p>
  
  <pre><code>Class.forName("org.apache.tomcat.jni.SSL", false, OpenSsl.class.getClassLoader());
  </code></pre>
  
  <p>throws an exception.
  Do I do something wrong, or is this some resurgence of 
  lat years issues (<a href="https://github.com/relayrides/pushy/issues/303" rel="nofollow noreferrer">https://github.com/relayrides/pushy/issues/303</a> and <a href="https://github.com/netty/netty-tcnative/issues/136" rel="nofollow noreferrer">https://github.com/netty/netty-tcnative/issues/136</a>)? 
  // working on 64 bit Win 10 with Oracle Java 1.8.21</p>