sync: fix recursive fetching

Commit b2fa30a2b8 ("sync: switch network
fetch to multiprocessing") accidentally changed the variable passed to
the 2nd fetch call from |missing| to |to_fetch| due to a copy & paste
of the earlier changed logic.  Undo that to fix git submodule fetching.

Bug: https://crbug.com/gerrit/14489
Change-Id: I627954f80fd2e80d9d5809b530aa6b0ef9260abb
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/305262
Reviewed-by: Raman Tenneti <rtenneti@google.com>
Tested-by: Mike Frysinger <vapier@google.com>

git_config.py

@@ -459,6 +459,11 @@ def init_ssh():
 def _open_ssh(host, port=None):
   global _ssh_master
 
+  # Bail before grabbing the lock if we already know that we aren't going to
+  # try creating new masters below.
+  if sys.platform in ('win32', 'cygwin'):
+    return False
+
   # Acquire the lock.  This is needed to prevent opening multiple masters for
   # the same host when we're running "repo sync -jN" (for N > 1) _and_ the
   # manifest <remote fetch="ssh://xyz"> specifies a different host from the
@@ -476,11 +481,8 @@ def _open_ssh(host, port=None):
     if key in _master_keys:
       return True
 
-    if (not _ssh_master
+    if not _ssh_master or 'GIT_SSH' in os.environ:
-            or 'GIT_SSH' in os.environ
+      # Failed earlier, so don't retry.
-            or sys.platform in ('win32', 'cygwin')):
-      # failed earlier, or cygwin ssh can't do this
-      #
       return False
 
     # We will make two calls to ssh; this is the common part of both calls.

subcmds/sync.py

@@ -887,7 +887,7 @@ later is required to fix a server side protocol bug.
         if previously_missing_set == missing_set:
           break
         previously_missing_set = missing_set
-        success, new_fetched = self._Fetch(to_fetch, opt, err_event)
+        success, new_fetched = self._Fetch(missing, opt, err_event)
         if not success:
           err_event.set()
         fetched.update(new_fetched)