Revert "Migrate git-repo to create private changes rather than drafts"

This reverts commit d88f53e2b9634b9645f80b2d8e653beac24711fe. I merged
it too hastily without paying enough attention to compatibility with
released Gerrit versions.

Change-Id: I4028d4737df1255f11e217da183a19a010597d5b
diff --git a/project.py b/project.py
index 5e20951..0b7baee 100644
--- a/project.py
+++ b/project.py
@@ -175,12 +175,14 @@
 
   def UploadForReview(self, people,
                       auto_topic=False,
+                      draft=False,
                       private=False,
                       wip=False,
                       dest_branch=None):
     self.project.UploadForReview(self.name,
                                  people,
                                  auto_topic=auto_topic,
+                                 draft=draft,
                                  private=private,
                                  wip=wip,
                                  dest_branch=dest_branch)
@@ -1108,6 +1110,7 @@
   def UploadForReview(self, branch=None,
                       people=([], []),
                       auto_topic=False,
+                      draft=False,
                       private=False,
                       wip=False,
                       dest_branch=None):
@@ -1153,7 +1156,12 @@
     if dest_branch.startswith(R_HEADS):
       dest_branch = dest_branch[len(R_HEADS):]
 
-    ref_spec = '%s:refs/for/%s' % (R_HEADS + branch.name, dest_branch)
+    upload_type = 'for'
+    if draft:
+      upload_type = 'drafts'
+
+    ref_spec = '%s:refs/%s/%s' % (R_HEADS + branch.name, upload_type,
+                                  dest_branch)
     if auto_topic:
       ref_spec = ref_spec + '/' + branch.name