postinstall: remove call to ogFixBootSector script

Remove call to ogFixBootSector function as it is possibly only
required by Windows XP and FAT filesystem.

src/utils/postinstall.py

@@ -140,19 +140,6 @@ def windows_register_c_drive(disk, partition):
         umount(mountpoint)
 
 
-def configure_mbr_boot_sector(disk, partition):
-    cmd_configure = f"ogFixBootSector {disk} {partition}"
-
-    proc = subprocess.run(cmd_configure,
-                          stdout=subprocess.DEVNULL,
-                          stderr=subprocess.DEVNULL,
-                          encoding='utf-8',
-                          shell=True,
-                          check=True)
-    if proc.returncode != 0:
-        logging.warning(f'{cmd_configure} returned non-zero exit status {proc.returncode}')
-
-
 def configure_fstab(disk, partition):
     logging.info(f'Configuring /etc/fstab')
     device = get_partition_device(disk, partition)
@@ -188,8 +175,6 @@ def configure_os_windows(disk, partition):
 
         _, _, esp_part_number = get_efi_partition(disk, enforce_gpt=True)
         install_main_grub()
-    else:
-        configure_mbr_boot_sector(disk, partition)
 
     update_bcd(disk, partition)
     windows_register_c_drive(disk, partition)