Fix errors when clone.bundle missing on server

Catch curl failures to download clone.bundle; don't let git try to parse
the 404 page as a bundle file (was causing much user confusion).

This should eliminate false error messages from init and sync such as:
  error: '.repo/manifests.git/clone.bundle' does not look like a v2 bundle file
  fatal: Could not read bundle '.repo/manifests.git/clone.bundle'.
  error: RPC failed; result=22, HTTP code = 400

Signed-off-by: Matt Gumbel <matthew.k.gumbel@intel.com>
Change-Id: I7994f7c0baecfb45bb5a5850c48bd2a0ffabe773
1 file changed