Drop dependency on deprecated sonar-graph

pom.xml

@@ -446,11 +446,6 @@
         <artifactId>sonar-home</artifactId>
         <version>${project.version}</version>
       </dependency>
-      <dependency>
-        <groupId>org.codehaus.sonar</groupId>
-        <artifactId>sonar-graph</artifactId>
-        <version>5.1</version>
-      </dependency>
       <dependency>
         <groupId>${project.groupId}</groupId>
         <artifactId>sonar-plugin-api</artifactId>

sonar-plugin-api/pom.xml

@@ -78,12 +78,6 @@
         </exclusion>
       </exclusions>
     </dependency>
-    <dependency>
-      <!-- to be kept for backward-compatibility of org.sonar.api.design.Dependency -->
-      <groupId>org.codehaus.sonar</groupId>
-      <artifactId>sonar-graph</artifactId>
-    </dependency>
-
 
     <!--
       Transitive dependencies available at runtime. They are not shaded with API

sonar-plugin-api/src/main/java/org/sonar/graph/Edge.java

@@ -0,0 +1,34 @@
+/*
+ * SonarQube
+ * Copyright (C) 2009-2017 SonarSource SA
+ * mailto:info AT sonarsource DOT com
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU Lesser General Public
+ * License as published by the Free Software Foundation; either
+ * version 3 of the License, or (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
+ * Lesser General Public License for more details.
+ *
+ * You should have received a copy of the GNU Lesser General Public License
+ * along with this program; if not, write to the Free Software Foundation,
+ * Inc., 51 Franklin Street, Fifth Floor, Boston, MA  02110-1301, USA.
+ */
+package org.sonar.graph;
+
+/**
+ * @deprecated in 5.2. See {@link org.sonar.api.design.Dependency}
+ */
+@Deprecated
+public interface Edge<V> {
+
+  int getWeight();
+
+  V getFrom();
+
+  V getTo();
+
+}