updated prepdecrypt.sh

#!/sbin/sh
#
# If properties need to be set from system's build.prop, then add the BoardConfig flag
# TW_OVERRIDE_SYSTEM_PROPS := "ro.build.version.release;ro.build.version.security_patch"
# to use the build.prop values for decryption. No mounting needs to be done via this script
#
finish()
{
	setprop crypto.ready 1
	exit 0
}

osver=$(getprop ro.build.version.release)
osver_orig=$(getprop ro.build.version.release_orig)
patchlevel=$(getprop ro.build.version.security_patch)
patchlevel_orig=$(getprop ro.build.version.security_patch_orig)

# Be sure to increase the PLATFORM_VERSION in build/core/version_defaults.mk to override Google's anti-rollback features to something rather insane
if [ -z "$osver" ]; then
	if [ -n "$osver_orig" ]; then
		setprop ro.build.version.release "$osver_orig"
		echo "ro.build.version.release=$osver_orig" >> "/$DEFAULTPROP";
	else
		osver="16.1.0"
		setprop ro.build.version.release "$osver"
		echo "ro.build.version.release=$osver" >> "/$DEFAULTPROP";
	fi
fi
if [ -z "$patchlevel" ]; then
	if [ -n "$patchlevel_orig" ]; then
		setprop ro.build.version.security_patch "$patchlevel_orig"
		echo "ro.build.version.security_patch=$patchlevel_orig" >> "/$DEFAULTPROP";
		finish
	else
		patchlevel="2099-12-31"
		setprop ro.build.version.security_patch "$patchlevel"
		echo "ro.build.version.security_patch=$patchlevel" >> "/$DEFAULTPROP";
		finish
	fi
else
	finish
fi