Prevent a crash during path verification

Swallow TFS exceptions for this non critical part of the clone process...

Permit to clone a branch and use git-tfs even when, due to a bug in TFS,
TFS is broken and return an error TF14045 when asking for branches.
Merge pull request #557 from pmiossec/prevent_crash_during_branch_verification

Prevent a crash during path verification
correct `--no-fetch` option