Ensure only the filtered environment variables are inherited from the OS

The recent change which modified inheritFromOS to use the intial
environment, rather than the current environment, introduced a bug such
that variables which had been cleaned from the environment where still set
in the data store.

This patch changes things such that a list of approved environment
variables is saved after the environment is cleaned and only the variables
in this list are inherited in inheritFromOS.

CC: James Limbouris <james.limbouris@gmail.com>
CC: Chris Larson <clarson@kergoth.com>
(Bitbake rev: cb6c07054e8baf94614713ec257c643b22266d75)

Signed-off-by: Joshua Lock <josh@linux.intel.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/data.py

@@ -159,16 +159,17 @@ def expandKeys(alterdata, readdata = None):
         ekey = todolist[key]
         renameVar(key, ekey, alterdata)
 
-def inheritFromOS(d, savedenv):
+def inheritFromOS(d, savedenv, permitted):
     """Inherit variables from the initial environment."""
     exportlist = bb.utils.preserved_envvars_exported()
     for s in savedenv.keys():
-        try:
-            setVar(s, getVar(s, savedenv, True), d)
-            if s in exportlist:
-                setVarFlag(s, "export", True, d)
-        except TypeError:
-            pass
+        if s in permitted:
+            try:
+                setVar(s, getVar(s, savedenv, True), d)
+                if s in exportlist:
+                    setVarFlag(s, "export", True, d)
+            except TypeError:
+                pass
 
 def emit_var(var, o=sys.__stdout__, d = init(), all=False):
     """Emit a variable to be sourced by a shell."""