Update JGit to 0.5.1.140-g660fd39

This is very close to what will eventually be the 0.7.0 release
from the Eclipse.org domain.

It resolves both issues 304 and 399 for us.  Issue 304 was about
not reporting "git not found" during replication when git was not
in the remote user's $PATH.  Issue 399 was about JGit rejecting
older format annotated tag objects, where the tagger was missing.
The Linux kernel is one such project with old tags like this,
which made it hard to work with the kernel in Gerrit.

Bug: issue 304
Bug: issue 399
Change-Id: Icb6252fa549a1814c0334332750552d531fdc0bf
Signed-off-by: Shawn O. Pearce <sop@google.com>
Reviewed-by: Nico Sallembien <nsallembien@google.com>

gerrit-sshd/src/main/java/com/google/gerrit/sshd/commands/AdminCreateProject.java

@@ -30,6 +30,7 @@ import com.google.inject.Inject;
 
 import org.apache.sshd.server.Environment;
 import org.eclipse.jgit.lib.Constants;
+import org.eclipse.jgit.lib.RefUpdate;
 import org.eclipse.jgit.lib.Repository;
 import org.kohsuke.args4j.Option;
 
@@ -90,7 +91,11 @@ final class AdminCreateProject extends BaseCommand {
 
           Repository repo = repoManager.createRepository(projectName);
           repo.create(true);
-          repo.writeSymref(Constants.HEAD, branch);
+
+          RefUpdate u = repo.updateRef(Constants.HEAD);
+          u.disableRefLog();
+          u.link(branch);
+
           repoManager.setProjectDescription(projectName, projectDescription);
 
           createProject();