bitbake: utils: remove BB_ENV_PASSTHROUGH from preserved_envvars()

preserved_envvars() is used when the BB_ENV_PASSTHROUGH
environment variable is not set. Therefore, its code shouldn't
return this variable.

(Bitbake rev: 0a33b560233b983456178541603ab96fea22238b)

Signed-off-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Reported-by: Robert P. J. Day <rpjday@crashcourse.ca>
Tested-by: Michael Opdenacker <michael.opdenacker@bootlin.com>
Signed-off-by: Richard Purdie <richard.purdie@linuxfoundation.org>

bitbake/lib/bb/utils.py

@@ -604,7 +604,6 @@ def preserved_envvars():
     v = [
         'BBPATH',
         'BB_PRESERVE_ENV',
-        'BB_ENV_PASSTHROUGH',
         'BB_ENV_PASSTHROUGH_ADDITIONS',
     ]
     return v + preserved_envvars_exported()