sync: Improve error message when writing smart sync manifest fails

The error message only states that writing the manifest failed.

Include the exception message, so it's easier to track down the reason
that the write failed.

Change-Id: I06e942c48a19521ba45292199519dd0a8bdb1de7

1 files changed, 3 insertions, 2 deletions

diff --git a/subcmds/sync.py b/subcmds/sync.py
index b4546c15..c9ca8897 100644
--- a/subcmds/sync.py
+++ b/subcmds/sync.py
@@ -592,8 +592,9 @@ later is required to fix a server side protocol bug.
               f.write(manifest_str)
             finally:
               f.close()
-          except IOError:
-            print('error: cannot write manifest to %s' % manifest_path,
+          except IOError as e:
+            print('error: cannot write manifest to %s:\n%s'
+                  % (manifest_path, e),
                   file=sys.stderr)
             sys.exit(1)
           self._ReloadManifest(manifest_name)