Error rendering Test Run table caused by the Test Run Defects column

An Null Pointer exception occurs rendering the Test Runs table when the step of a Test Run step defect has been deleted.

java.lang.NullPointerException com.xpandit.raven.layout.columns.test.TestTestRunColumnLayoutItemRendererImpl.a com.xpandit.raven.layout.columns.test.TestTestRunColumnLayoutItemRendererImpl.a

Steps to reproduce:

• Create a Test at least one step
• Create a Test Run and create a step defect on step #1
• Go back to the Test issue and delete the first step
• Refresh the page and an exception occurs rendering the Test Runs table