Fix SELinux warning when passing fuse FD from system server.

Before applying the CL, Android shows the following error when passing
FD of /dev/fuse.

> Binder_2: type=1400 audit(0.0:38): avc: denied { getattr } for
> path="/dev/fuse" dev="tmpfs" ino=9300 scontext=u:r:system_server:s0
> tcontext=u:object_r:fuse_device:s0 tclass=chr_file permissive=0

Change-Id: I59dec819d79d4e2e1a8e42523b6f521481cb2afd

system_server.te

@@ -441,7 +441,7 @@ userdebug_or_eng(`
 
 # For AppFuse.
 allow system_server vold:fd use;
-allow system_server fuse_device:chr_file { read write ioctl };
+allow system_server fuse_device:chr_file { read write ioctl getattr };
 
 # Connect to adbd and use a socket transferred from it.
 # Used for e.g. jdwp.