Test: Fix hook.py: AttributeError

  File "/vpp/test/hook.py", line 84, in on_crash
    self.testcase.vpp_bin, core_path)
AttributeError: 'PollHook' object has no attribute 'testcase'

Change-Id: I84d9d86a5c6a5769a43a91cf23ce8a1141f7cd12
Signed-off-by: Paul Vinciguerra <pvinci@vinciconsulting.com>
diff --git a/test/hook.py b/test/hook.py
index 187e13e..6c971c9 100644
--- a/test/hook.py
+++ b/test/hook.py
@@ -81,7 +81,7 @@
 
     def on_crash(self, core_path):
         self.logger.error("Core file present, debug with: gdb %s %s",
-                          self.testcase.vpp_bin, core_path)
+                          self.test.vpp_bin, core_path)
         check_core_path(self.logger, core_path)
         self.logger.error("Running `file %s':", core_path)
         try: