lib/oe/sstatesig: fix wildcard matching wrong task signature files

With a '*' as a wildcard for the signature here we can also match a
portion of the task name with the result that we may match a sigdata
file for the wrong task. Luckily the signature is always the same
length - 32 characters - so we can simply use 32 '?' characters instead.
(A regex would have been another alternative, but the wildcard should be
effective and I felt like a regex would complicate the code more than
this solution).

Fixes [YOCTO #11763].

(From OE-Core rev: 73c6f85457361cd82d44838946aa81ba9bd1662a)

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

meta/lib/oe/sstatesig.py

@@ -320,7 +320,7 @@ 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 ['*']
+        hashes = taskhashlist or ['?' * 32]
         localdata = bb.data.createCopy(d)
         for hashval in hashes:
             localdata.setVar('PACKAGE_ARCH', '*')