bitbake: siggen: Clean up task reference formats

Currently siggen uses the format "<filename>.<taskname>" for referencing tasks
whilst runqueue uses "<filename>:<taskname>". This converts to use ":" as the
separator everywhere.

This is an API breaking change since the cache is affected, as are siginfo files
and any custom signature handlers such as those in OE-Core.

Ultimately this will let us clean up and the accessor functions from runqueue,
removing all the ".rsplit(".", 1)[0]" type code currently all over the place.
Once a standard is used everwhere we can update the code over time to be more
optimal.

(Bitbake rev: 07e539e1c566ca3434901e1a00335cb76c69d496)

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

bitbake/lib/bb/tests/data.py

@@ -466,7 +466,7 @@ class TaskHash(unittest.TestCase):
             tasklist, gendeps, lookupcache = bb.data.generate_dependencies(d)
             taskdeps, basehash = bb.data.generate_dependency_hash(tasklist, gendeps, lookupcache, set(), "somefile")
             bb.warn(str(lookupcache))
-            return basehash["somefile." + taskname]
+            return basehash["somefile:" + taskname]
 
         d = bb.data.init()
         d.setVar("__BBTASKS", ["mytask"])