clone: checkout the "default" branch if available

mercurial/hg.py

@@ -218,7 +218,11 b' def clone(ui, source, dest=None, pull=Fa'
             dest_lock.release()
 
         if update:
-            _update(dest_repo, dest_repo.changelog.tip())
+            try:
+                checkout = dest_repo.lookup("default")
+            except:
+                checkout = dest_repo.changelog.tip()
+            _update(dest_repo, checkout)
     if dir_cleanup:
         dir_cleanup.close()