No longer used (#260).

src/main/java/org/gitlab4j/api/models/ErrorMessage.java

-
-package org.gitlab4j.api.models;
-
-import javax.xml.bind.annotation.XmlAccessType;
-import javax.xml.bind.annotation.XmlAccessorType;
-import javax.xml.bind.annotation.XmlRootElement;
-
-@XmlRootElement
-@XmlAccessorType(XmlAccessType.FIELD)
-public class ErrorMessage {
-
-    private String message;
-
-    public String getMessage() {
-        return this.message;
-    }
-
-    public void setMessage(String message) {
-        this.message = message;
-    }
-}