Remove unreleased version constant

Some people apparently never run tests when they change this file.
Neither do they read comments right below the line they change that
they should do the change after all.

core/src/main/java/org/elasticsearch/Version.java

@@ -89,8 +89,6 @@ public class Version {
     public static final Version V_5_0_0_beta1 = new Version(V_5_0_0_beta1_ID, org.apache.lucene.util.Version.LUCENE_6_2_0);
     public static final int V_5_0_0_rc1_ID = 5000051;
     public static final Version V_5_0_0_rc1 = new Version(V_5_0_0_rc1_ID, org.apache.lucene.util.Version.LUCENE_6_2_0);
-    public static final int V_5_0_0_ID = 5000099;
-    public static final Version V_5_0_0 = new Version(V_5_0_0_ID, org.apache.lucene.util.Version.LUCENE_6_2_0);
     public static final int V_6_0_0_alpha1_ID = 6000001;
     public static final Version V_6_0_0_alpha1 = new Version(V_6_0_0_alpha1_ID, org.apache.lucene.util.Version.LUCENE_6_2_0);
     public static final Version CURRENT = V_6_0_0_alpha1;
@@ -117,8 +115,6 @@ public class Version {
         switch (id) {
             case V_6_0_0_alpha1_ID:
                 return V_6_0_0_alpha1;
-            case V_5_0_0_ID:
-                return V_5_0_0;
             case V_5_0_0_rc1_ID:
                 return V_5_0_0_rc1;
             case V_5_0_0_beta1_ID: