allow init to run mke2fs tools to format partitions

Test: let fs_mgr format a damaged /data partition
Bug: 35219933
Change-Id: If92352ea7a70780e9d81ab10963d63e16b793792
(cherry picked from commit 5f573ab2aa8f566c723f4ddd576f8365dcaec191)
diff --git a/private/genfs_contexts b/private/genfs_contexts
index 54e9a2c..3914cec 100644
--- a/private/genfs_contexts
+++ b/private/genfs_contexts
@@ -56,6 +56,7 @@
 genfscon sysfs /devices/virtual/block/zram0/uevent    u:object_r:sysfs_zram_uevent:s0
 genfscon sysfs /devices/virtual/block/zram1/uevent    u:object_r:sysfs_zram_uevent:s0
 genfscon sysfs /devices/virtual/misc/hw_random    u:object_r:sysfs_hwrandom:s0
+genfscon sysfs /fs/ext4/features                  u:object_r:sysfs_fs_ext4_features:s0
 genfscon sysfs /power/wake_lock u:object_r:sysfs_wake_lock:s0
 genfscon sysfs /power/wake_unlock u:object_r:sysfs_wake_lock:s0
 genfscon sysfs /kernel/uevent_helper u:object_r:usermodehelper:s0