lib/sstatesig: Update to longer sha256 hash length

Update the code to match the recent switch to sha256 hashes

(From OE-Core rev: 910a8f3e8e350ff5d316faf5e07fb40c6c51f45e)

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

meta/lib/oe/sstatesig.py

@@ -494,7 +494,7 @@ def find_siginfo(pn, taskname, taskhashlist, d):
 
     if not taskhashlist or (len(filedates) < 2 and not foundall):
         # That didn't work, look in sstate-cache
-        hashes = taskhashlist or ['?' * 32]
+        hashes = taskhashlist or ['?' * 64]
         localdata = bb.data.createCopy(d)
         for hashval in hashes:
             localdata.setVar('PACKAGE_ARCH', '*')