commitgraph package: fix exports/imports, add @since tag for new API

Change-Id: I9175b1d796f91f5ba4e21d3418550ae451c054b0

org.eclipse.jgit.test/META-INF/MANIFEST.MF

@@ -37,6 +37,7 @@ Import-Package: com.googlecode.javaewah;version="[1.1.6,2.0.0)",
  org.eclipse.jgit.internal.diffmergetool;version="[6.5.0,6.6.0)",
  org.eclipse.jgit.internal.fsck;version="[6.5.0,6.6.0)",
  org.eclipse.jgit.internal.revwalk;version="[6.5.0,6.6.0)",
+ org.eclipse.jgit.internal.storage.commitgraph;version="6.5.0",
  org.eclipse.jgit.internal.storage.dfs;version="[6.5.0,6.6.0)",
  org.eclipse.jgit.internal.storage.file;version="[6.5.0,6.6.0)",
  org.eclipse.jgit.internal.storage.io;version="[6.5.0,6.6.0)",

org.eclipse.jgit/META-INF/MANIFEST.MF

@@ -81,6 +81,7 @@ Export-Package: org.eclipse.jgit.annotations;version="6.5.0",
   x-friends:="org.eclipse.jgit.test",
  org.eclipse.jgit.internal.revwalk;version="6.5.0";
   x-friends:="org.eclipse.jgit.test",
+ org.eclipse.jgit.internal.storage.commitgraph;version="6.5.0",
  org.eclipse.jgit.internal.storage.dfs;version="6.5.0";
   x-friends:="org.eclipse.jgit.test,
    org.eclipse.jgit.http.server,

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/commitgraph/CommitGraphWriter.java

@@ -43,6 +43,8 @@
 
 /**
  * Writes a commit-graph formatted file.
+ *
+ * @since 6.5
  */
 public class CommitGraphWriter {
 

org.eclipse.jgit/src/org/eclipse/jgit/internal/storage/commitgraph/GraphCommits.java

@@ -36,6 +36,8 @@
  * <li>List commits in SHA1 order.</li>
  * <li>Get the position of a specific SHA1 in the list.</li>
  * </ul>
+ *
+ * @since 6.5
  */
 public class GraphCommits implements Iterable<RevCommit> {