Allow sync to run even when the manifest is broken.

If the current manifest is broken then "repo sync" fails because it
can't retrieve the default value for --jobs. Use 1 in this case, in
order that you can "repo sync" to get a fixed manifest (assuming someone
fixed it upstream).

Change-Id: I4262abb59311f1e851ca2a663438a7e9f796b9f6

subcmds/sync.py

diff --git a/subcmds/sync.py b/subcmds/sync.py
index f809473..228a279 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -51,7 +51,7 @@
 from project import Project
 from project import RemoteSpec
 from command import Command, MirrorSafeCommand
-from error import RepoChangedException, GitError
+from error import RepoChangedException, GitError, ManifestParseError
 from project import SyncBuffer
 from progress import Progress
 
@@ -148,7 +148,10 @@
 """
 
   def _Options(self, p, show_smart=True):
-    self.jobs = self.manifest.default.sync_j
+    try:
+      self.jobs = self.manifest.default.sync_j
+    except ManifestParseError:
+      self.jobs = 1
 
     p.add_option('-f', '--force-broken',
                  dest='force_broken', action='store_true',