Fix #939 where setter was getting named the same as the getter

Author: bkelley17

src/main/java/io/swagger/codegen/v3/generators/java/AbstractJavaCodegen.java

@@ -1033,7 +1033,7 @@ protected void fixUpParentAndInterfaces(CodegenModel codegenModel, Map<String, C
                 if (hasConflict) {
                     codegenProperty.name = toVarName(codegenModel.name + "_" + codegenProperty.name);
                     codegenProperty.getter = toGetter(codegenProperty.name);
-                    codegenProperty.setter = toGetter(codegenProperty.name);
+                    codegenProperty.setter = toSetter(codegenProperty.name);
                     break;
                 }
                 parentModel = parentModel.parentModel;