bitbake: siggen: Change exception note into a warning

This makes no sense as just a note, its at least a warning and useful
to get an idea of which codepath is failing.

(Bitbake rev: 0194cf0da24dc72dab0612cd54aa5190e6cd92f2)

Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/siggen.py

@@ -146,7 +146,7 @@ class SignatureGeneratorBasic(SignatureGenerator):
         try:
             taskdeps = self._build_data(fn, d)
         except:
-            bb.note("Error during finalise of %s" % fn)
+            bb.warn("Error during finalise of %s" % fn)
             raise
 
         #Slow but can be useful for debugging mismatched basehashes