Add unit tests for bandit.core.issue
Add unit tests for bandit.core.issue

Brings coverage for bandit.core.issue to 100%.

Change-Id: I67dfbb64cb276d1c16b28e4bbc6b50c8254bd3f1

pombredanne/bandit,pombredanne/bandit,stackforge/bandit,chair6/bandit,stackforge/bandit