SERVER-36452 Avoid compile failures on OS X if system headers add more SSLProtocol enum cases

Author: GeertBosch

src/mongo/util/net/ssl_manager_apple.cpp

@@ -1296,6 +1296,7 @@ void recordTLSVersion(::SSLContextRef ssl) {
         case kTLSProtocol1Only:
         case kSSLProtocolAll:
         case kDTLSProtocol1:
+        default:  // Some system headers may define additional protocols, so suppress warnings.
             // Do nothing
             break;
     }