Ensure files are created with 0600 perms

Network Manager in Rocky Linux 10 is complaning on 100644 for
.nmconnection keyfiles

Change-Id: I36085f721408dfb33f6a1bf9b599ced5382fc4f1
Signed-off-by: Michal Nasiadka <mnasiadka@gmail.com>

glean/cmd.py

@@ -1394,6 +1394,7 @@ def finish_files(files_to_write, args):
                 log.debug("Writing output file : %s" % k)
                 with safe_open(k, 'w') as outfile:
                     outfile.write(files_to_write[k])
+
                 log.debug(" ... done")
                 break
             except IOError as e:
@@ -1412,6 +1413,10 @@ def finish_files(files_to_write, args):
                 else:
                     raise
 
+        if '/etc/NetworkManager/system-connections/' in k:
+            # NetworkManager refuses to load nmconnection files with 644 perms
+            os.chmod(k, 0o600)
+
 
 def is_interface_live(interface, sys_root):
     try:

glean/tests/test_glean.py

@@ -176,7 +176,9 @@ class TestGlean(base.BaseTestCase):
                 new_callable=mock.Mock)
     @mock.patch('glean.cmd.is_keyfile_format', return_value=False,
                 new_callable=mock.Mock)
+    @mock.patch('os.chmod', return_value=0, new_callable=mock.Mock)
     def _assert_distro_provider(self, distro, provider, interface,
+                                mock_os_chmod,
                                 mock_is_keyfile,
                                 mock_vendor_linux_distribution,
                                 mock_open,