Revert "Preserve environment variables with buildah"

This reverts commit 140fc48e73.

Reason for revert:
The original change breaks authentication without authfile.

Closes-Bug: #1999749
Change-Id: Ifbfba09c8ac552cc3c18adb482540541a282488b

tripleo_common/image/builder/buildah.py

@@ -94,7 +94,7 @@ class BuildahBuilder(base.BaseBuilder):
                          'Containerfile' in fnames}
         # Building images with root so overlayfs is used, and not fuse-overlay
         # from userspace, which would be slower.
-        self.buildah_cmd = ['sudo', '-E', 'buildah']
+        self.buildah_cmd = ['sudo', 'buildah']
         if self.debug:
             self.buildah_cmd.append('--log-level=debug')
 

tripleo_common/tests/image/builder/test_buildah.py

@@ -25,7 +25,7 @@ from tripleo_common.tests import base
 from tripleo_common.utils import process
 
 
-BUILDAH_CMD_BASE = ['sudo', '-E', 'buildah']
+BUILDAH_CMD_BASE = ['sudo', 'buildah']
 DEPS = {"base"}
 WORK_DIR = '/tmp/kolla'
 VOLS = ['/etc/pki:/etc/pki', '/etc/dir2:/dir2']