remove $ from class name

it is cased because the property start with underscore and
object is created on th fly

fix #2191

modules/swagger-codegen/src/main/java/io/swagger/codegen/languages/PhpClientCodegen.java

@@ -372,6 +372,10 @@ public class PhpClientCodegen extends DefaultCodegen implements CodegenConfig {
         return camelize(name);
     }
 
+    public static String camelize(String word) {
+        return DefaultCodegen.camelize(word).replaceAll("\\$", "");
+    }
+
     @Override
     public String toModelFilename(String name) {
         // should be the same as the model name