Suppress IDE warnings on Java 8 MR3 methods

If IntelliJ is configured with a project SDK newer than JDK 8, it will
emit build-breaking errors on uses of methods that were added in newer
versions and later backported to Java 8, such as the ALPN support added
in Maintenance Release 3 (`setApplicationProtocols()`), because they are
documented as `@since 9` or `@since 11` in Javadoc. This change
suppresses those warnings, since we know these methods are safe to use.

Author: rschmitt

httpclient5/src/main/java/org/apache/hc/client5/http/impl/io/DefaultHttpClientConnectionOperator.java

@@ -299,6 +299,7 @@ private void connectToUnixDomainSocket(
         }
     }
 
+    @SuppressWarnings("Since15")
     private static void configureSocket(final Socket socket, final SocketConfig socketConfig,
                                         final Timeout soTimeout) throws IOException {
         if (soTimeout != null) {

httpclient5/src/main/java/org/apache/hc/client5/http/ssl/DefaultClientTlsStrategy.java

@@ -151,6 +151,7 @@ public DefaultClientTlsStrategy(final SSLContext sslContext) {
     }
 
     @Override
+    @SuppressWarnings("Since15")
     void applyParameters(final SSLEngine sslEngine, final SSLParameters sslParameters, final String[] appProtocols) {
         sslParameters.setApplicationProtocols(appProtocols);
         sslEngine.setSSLParameters(sslParameters);