Set:

BB_SIGNATURE_HANDLER = "noop"

Then we will get the following errors:

  File "/build/poky-new/bitbake/lib/bb/runqueue.py", line 876, in RunQueue._start_worker(fakeroot=False, rqexec=None):
                 "fakerootnoenv" : self.rqdata.dataCache.fakerootnoenv,
    >            "hashes" : bb.parse.siggen.taskhash,
                 "hash_deps" : bb.parse.siggen.runtaskdeps,
AttributeError: 'SignatureGenerator' object has no attribute 'taskhash'

This patch *seems* fix the problem, will send it to mailing list sooner:

diff --git a/bitbake/lib/bb/siggen.py b/bitbake/lib/bb/siggen.py
index bc96fd3..a45fc4c 100644
--- a/bitbake/lib/bb/siggen.py
+++ b/bitbake/lib/bb/siggen.py
@@ -34,6 +34,9 @@ class SignatureGenerator(object):
     name = "noop"
 
     def __init__(self, data):
+        self.taskhash = {}
+        self.runtaskdeps = {}
+        self.file_checksum_values = {}
         return
 
     def finalise(self, fn, d, varient):
@@ -42,7 +45,7 @@ class SignatureGenerator(object):
     def get_taskhash(self, fn, task, deps, dataCache):
         return "0" 
 
-    def set_taskdata(self, hashes, deps):
+    def set_taskdata(self, hashes, deps, checksum):
         return
 
     def stampfile(self, stampbase, file_name, taskname, extrainfo):