title: Jgit RevWalk.parseCommit() throw MissingObjectException
body: <p>I have a repository with some test commit (all on default branch).
  Using JGit log command, I can see these commit ( for exemple):</p>
  
  <pre><code>RepositoryBuilder builder = new RepositoryBuilder();
  Repository repository = builder.setWorkTree("/tmp/myworkingdir").readEnvironment().findGitDir().build();
  Git git = new Git(repository);
  
  for (RevCommit commit : git.log().call()) {
      System.out.println("commit: " + commit.getId());
  }
  </code></pre>
  
  <p>Result:</p>
  
  <pre><code>commit: commit f34a848371ff334b2e85aa16fbf9b871d028b443 1371652639 ----sp
  commit: commit 33603f8c1c47712d45eb0db4b1827bbd113c2428 1371652639 ----sp
  commit: commit d52bd5c768263a957d99975f5482020ffc3434d5 1371652639 ----sp
  </code></pre>
  
  <p>But when I try to get a RevCommit from the String SHA1 it fails on the last line of this snippet:</p>
  
  <pre><code>ObjectId revid = repository.resolve("33603f8c1c47712d45eb0db4b1827bbd113c2428");
  RevWalk revWalk = new RevWalk(repository);
  RevCommit commit = revWalk.parseCommit(revid);
  </code></pre>
  
  <p>Exception:</p>
  
  <pre><code>org.eclipse.jgit.errors.MissingObjectException: Missing unknown 33603f8c1c47712d45eb0db4b1827bbd113c2428
  at org.eclipse.jgit.storage.file.WindowCursor.open(WindowCursor.java:126)
  at org.eclipse.jgit.lib.ObjectReader.open(ObjectReader.java:229)
  at org.eclipse.jgit.revwalk.RevWalk.parseAny(RevWalk.java:817)
  at org.eclipse.jgit.revwalk.RevWalk.parseCommit(RevWalk.java:730)
  </code></pre>
  
  <p>What am I doing wrong ?</p>
  
  <p><strong>Solution</strong>
  Init of the Repository was wrong on the access part..</p>