bitbake: bitbake: Drop older python version compatibility code

cooker: We can call multiprocessing close() unconditionally and tweak a
comment give 3.8 is now the minimum version.

lib/bb: We can drop the logger addition code only needed before 3.6

asyncrpc/hashserv: Since the minimum version is 3.8, we can drop the
conditional code.

(Bitbake rev: 16f4386400f88ba50605307961c248bef09895c1)

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

bitbake/lib/bb/cooker.py

@@ -1812,8 +1812,8 @@ class CookerCollectFiles(object):
             bb.event.fire(CookerExit(), eventdata)
 
         # We need to track where we look so that we can know when the cache is invalid. There
-        # is no nice way to do this, this is horrid. We intercept the os.listdir()
-        # (or os.scandir() for python 3.6+) calls while we run glob().
+        # is no nice way to do this, this is horrid. We intercept the os.listdir() and os.scandir()
+        # calls while we run glob().
         origlistdir = os.listdir
         if hasattr(os, 'scandir'):
             origscandir = os.scandir
@@ -2224,9 +2224,8 @@ class CookerParser(object):
 
         for process in self.processes:
             process.join()
-            # Added in 3.7, cleans up zombies
-            if hasattr(process, "close"):
-                process.close()
+            # clean up zombies
+            process.close()
 
         bb.codeparser.parser_cache_save()
         bb.codeparser.parser_cache_savemerge()