hob: handle sanity check failures as a separate event

In order to show a friendlier error message that does not bury the
actual sanity error in our typical preamble about disabling sanity
checks, use a separate event to indicate that sanity checks failed.

This change is intended to work together with the related change to
sanity.bbclass in OE-Core.

Fixes [YOCTO #2336].

(Bitbake rev: 24b631acdaa143a4de39c6e1328849660c66f219)

Signed-off-by: Paul Eggleton <paul.eggleton@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/event.py

@@ -527,3 +527,11 @@ class SanityCheckPassed(Event):
     """
     Event to indicate sanity check is passed
     """
+
+class SanityCheckFailed(Event):
+    """
+    Event to indicate sanity check has failed
+    """
+    def __init__(self, msg):
+        Event.__init__(self)
+        self._msg = msg