bitbake: lib: fix most undefined code picked up by pylint

Correctly import, and inherit functions, and variables.
Also fix some typos and remove some Python 2 code that isn't recognised.

(Bitbake rev: b0c807be5c2170c9481c1a04d4c11972135d7dc5)

Signed-off-by: Frazer Clews <frazerleslieclews@gmail.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/layerindexlib/restapi.py

@@ -5,9 +5,13 @@
 
 import logging
 import json
+import os
+
 from urllib.parse import unquote
 from urllib.parse import urlparse
 
+import bb
+
 import layerindexlib
 import layerindexlib.plugin
 
@@ -163,7 +167,7 @@ class RestApiPlugin(layerindexlib.plugin.IndexPlugin):
                     parsed = _get_json_response(apiurl=up_stripped.geturl(), username=username, password=password, retry=False)
                     logger.debug(1, "%s: retry successful.")
                 else:
-                    raise LayerIndexFetchError('%s: Connection reset by peer.  Is there a firewall blocking your connection?' % apiurl)
+                    raise layerindexlib.LayerIndexFetchError('%s: Connection reset by peer.  Is there a firewall blocking your connection?' % apiurl)
 
             return parsed