live: rewrite reboot operation

Add optional 'operation' parameter to _poweroff_oglive function.
Reuse _poweroff_oglive code before the busybox subprocess when rebooting
an ogLive client.

src/live/ogOperations.py

@@ -190,7 +190,7 @@ class OgLiveOperations:
             with open(logfile, 'wb', 0) as f:
                 f.truncate(0)
 
-    def _poweroff_oglive(self):
+    def _poweroff_oglive(self, operation='poweroff'):
         interface = os.getenv('DEVICE')
         cmd_ethtool = shlex.split(f'ethtool -s {interface} wol g')
         cmd_browser = shlex.split('pkill -9 browser')
@@ -198,7 +198,7 @@ class OgLiveOperations:
             busybox = 'busybox'
         else:
             busybox = shutil.which('busyboxOLD')
-        cmd_busybox = shlex.split(f'{busybox} poweroff')
+        cmd_busybox = shlex.split(f'{busybox} {operation}')
 
         umount_all()
         umount_cache()
@@ -219,9 +219,7 @@ class OgLiveOperations:
     def reboot(self):
         logging.info('Rebooting client')
         if os.path.exists('/scripts/oginit'):
-            cmd = f'source {ogClient.OG_PATH}etc/preinit/loadenviron.sh; ' \
-                  f'{ogClient.OG_PATH}scripts/reboot'
-            subprocess.call([cmd], shell=True, executable=OG_SHELL)
+            self._poweroff_oglive(operation='reboot')
         else:
             subprocess.call(['/sbin/reboot'])