Enable shallow fetch from a specific commit

This reverts commit f1f9815fbddd351aa498bb690c4e67148bdf7869.
diff --git a/project.py b/project.py
index b1ae8b6..914e0b1 100644
--- a/project.py
+++ b/project.py
@@ -1941,9 +1941,7 @@
 
     if not self.manifest.IsMirror:
       branch = self.revisionExpr
-      # gerrit 2.11 does not support this
-      enable = False
-      if is_sha1 and depth and git_require((1, 8, 3)) and enable:
+      if is_sha1 and depth and git_require((1, 8, 3)):
         # Shallow checkout of a specific commit, fetch from that commit and not
         # the heads only as the commit might be deeper in the history.
         spec.append(branch)