gitRepo: Fix an error due to missing TLS certificates

This was a problem when run inside a sandbox, e.g. via
"fetchRepoProject". The error message from repo seems unrelated:

fatal: Cannot get https://gerrit.googlesource.com/git-repo/clone.bundle
fatal: error no host given

But the exception is actually thrown due to missing certificates
(/etc/ssl/certs). It should be possible to provide another location via
environment variables (e.g. SSL_CERT_FILE, REQUESTS_CA_BUNDLE or
CURL_CA_BUNDLE) but apparently that doesn't actually work for some
reason (would have to study our Python packaging).

Now "fetchRepoProject" works without the "--no-clone-bundle" option.