[chore] Remove use of deprecated JRuby visitAll signature

Author: chadlwilson

src/main/java/org/jruby/rack/ext/Response.java

@@ -365,7 +365,7 @@ public IRubyObject write_headers(final ThreadContext context, final IRubyObject
     private static final ByteList NEW_LINE = new ByteList(new byte[] { '\n' }, false);
 
     protected void writeHeaders(final RackResponseEnvironment response) throws IOException {
-        this.headers.visitAll(new RubyHash.Visitor() { // headers.each { |key, val| }
+        this.headers.visitAll(getRuntime().getCurrentContext(), new RubyHash.Visitor() { // headers.each { |key, val| }
             @Override
             public void visit(final IRubyObject key, final IRubyObject val) {
                 final String name = key.toString();
@@ -424,7 +424,7 @@ else if ( val instanceof RubyTime ) {
 
                 response.addHeader(name, val.toString());
             }
-        });
+        }, null);
     }
 
     @JRubyMethod(name = "write_body")