Updating ITK superbuild version along 4.5.0 release branch

Change-Id: I7a1ab5cc018bcea0c2abe9ab36d6102d8a80ffbb
Merge topic 'SIMPLEITK-467_UpdateITKSuperbuildTowards4.5.1' into next

4b501fe5 Updating ITK superbuild version along 4.5.0 release branch