IncFS: update SE policies for the new API

IncFS in S adds a bunch of new ioctls, and requires the users
to read its features in sysfs directory. This change adds
all the features, maps them into the processes that need to
call into them, and allows any incfs user to query the features

Bug: 170231230
Test: incremental unit tests
Change-Id: Ieea6dca38ae9829230bc17d0c73f50c93c407d35
diff --git a/private/genfs_contexts b/private/genfs_contexts
index 900b25b..4e78804 100644
--- a/private/genfs_contexts
+++ b/private/genfs_contexts
@@ -140,6 +140,7 @@
 genfscon sysfs /firmware/devicetree/base/firmware/android u:object_r:sysfs_dt_firmware_android:s0
 genfscon sysfs /fs/ext4/features                  u:object_r:sysfs_fs_ext4_features:s0
 genfscon sysfs /fs/f2fs                           u:object_r:sysfs_fs_f2fs:s0
+genfscon sysfs /fs/incremental-fs/features        u:object_r:sysfs_fs_incfs_features:s0
 genfscon sysfs /power/autosleep u:object_r:sysfs_power:s0
 genfscon sysfs /power/state u:object_r:sysfs_power:s0
 genfscon sysfs /power/suspend_stats u:object_r:sysfs_suspend_stats:s0