If there is an intermittent network failure, we might be trying to reach
an URL multiple times. Without this patch, we would be re-adding the same
certificate to the OpenSSL default context multiple times.
Normally, this is no big issue, as OpenSSL will just silently ignore them,
after registering the error in its own error stack.
However, when python-cryptography initializes, it verifies that the current
error stack of the default OpenSSL context is empty, which it no longer is
due to us adding the certificates multiple times.
This results in cryptography throwing an Unknown OpenSSL Error with details:
OpenSSLErrorWithText(code=185057381L, lib=11, func=124, reason=101,
reason_text='error:0B07C065:x509 certificate routines:X509_STORE_add_cert:cert already in hash table'),
Signed-off-by: Patrick Uiterwijk <puiterwijk@redhat.com>
77af3a68de