Remove redundant backslashes

fleka8 reports:

  E502 the backslash is redundant between brackets

Fixed automatically with autopep8:

  git-repo $ git ls-files | grep py$ | xargs autopep8 --in-place --select E502

Change-Id: I1486ae1d17206918474363daf518274c5be8daed
Reviewed-on: https://gerrit-review.googlesource.com/c/git-repo/+/254602
Tested-by: David Pursehouse <dpursehouse@collab.net>
Reviewed-by: Mike Frysinger <vapier@google.com>

subcmds/sync.py

@@ -355,7 +355,7 @@ later is required to fix a server side protocol bug.
       except _FetchError:
         pass
       except Exception as e:
-        print('error: Cannot fetch %s (%s: %s)' \
+        print('error: Cannot fetch %s (%s: %s)'
             % (project.name, type(e).__name__, str(e)), file=sys.stderr)
         err_event.set()
         raise