Check for None before decoding alt subject name

[daviddavis]

Looks like when F25 upgraded from python-rhsm 1.19.0 to 1.19.4, our tests started failing:

rhsm.https: DEBUG: Using standard libs to provide httplib and ssl
rhsm.certificate2: ERROR: 'NoneType' object has no attribute 'decode'
Traceback (most recent call last):
  File "/usr/lib64/python2.7/site-packages/rhsm/certificate2.py", line 99, in _read_x509
    return self._create_v1_cert(version, extensions, x509, path)
  File "/usr/lib64/python2.7/site-packages/rhsm/certificate2.py", line 114, in _create_v1_cert
    return self._create_identity_cert(version, extensions, x509, path)
  File "/usr/lib64/python2.7/site-packages/rhsm/certificate2.py", line 137, in _create_identity_cert
    alt_name=self._read_alt_name(x509),
  File "/usr/lib64/python2.7/site-packages/rhsm/certificate2.py", line 121, in _read_alt_name
    return x509.get_extension(name='subjectAltName').decode('utf-8')
AttributeError: 'NoneType' object has no attribute 'decode'

Looks like the following change was introduced in that timeframe:

candlepin/python-rhsm@f3164e3#diff-b89afd85b4d5ab2767749c609cab6374R118

Bugzilla: https://bugzilla.redhat.com/show_bug.cgi?id=1445511

[candlepin-bot]

Can one of the admins verify this patch?

[awood]

bot, okay to test ok to test

[kahowell]

How un-pythonic... How about:

if alt_name is None:
    return None
else:
    return alt_name.decode('utf-8')

or similar?

[awood]

I agree with @kahowell. I prefer to avoid Python's ersatz ternary operator.

[daviddavis]

@kahowell @awood updated. thanks for the review.

[jirihnidek]

Damn, I should read properly an remember what others do: #1608

[daviddavis]

@jirihnidek Your change looks better. I'll close this out.