Removed unused imports.

Author: gmessner

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

@@ -1,7 +1,5 @@
 package org.gitlab4j.api.models;
 
-import com.fasterxml.jackson.annotation.JsonProperty;
-
 public class DiffRef {
     private String baseSha;
     private String headSha;

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

@@ -1,15 +1,16 @@
 package org.gitlab4j.api.models;
 
-import com.fasterxml.jackson.annotation.JsonProperty;
-import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
-import com.fasterxml.jackson.databind.annotation.JsonSerialize;
-import org.gitlab4j.api.utils.JacksonJson;
+import java.util.Date;
+import java.util.List;
 
 import javax.xml.bind.annotation.XmlAccessType;
 import javax.xml.bind.annotation.XmlAccessorType;
 import javax.xml.bind.annotation.XmlRootElement;
-import java.util.Date;
-import java.util.List;
+
+import org.gitlab4j.api.utils.JacksonJson;
+
+import com.fasterxml.jackson.databind.annotation.JsonDeserialize;
+import com.fasterxml.jackson.databind.annotation.JsonSerialize;
 
 @XmlRootElement
 @XmlAccessorType(XmlAccessType.FIELD)