temp fix for build breakage.

libsepol.check_assertion_helper: neverallow on line 8857 violated by allow system_server sdcard_external:file { ioctl read write getattr lock append open };
Error while expanding policy
make: *** [out/target/product/manta/obj/ETC/sepolicy_intermediates/sepolicy] Error 1

Change-Id: I181707ed66bad3db56f9084b3d9ba161d13b34bd