fstools: update to latest git HEAD

the recent fixes to make mount_root work during failsafe caused lots of
unwanted side effects. use the new preinit sentinel file to detect if
we are in preinit. this will also work if logged in via ssh.

Signed-off-by: John Crispin <john@phrozen.org>

package/system/fstools/Makefile

@@ -8,14 +8,14 @@
 include $(TOPDIR)/rules.mk
 
 PKG_NAME:=fstools
-PKG_VERSION:=2016-05-12
+PKG_VERSION:=2016-05-16
 
 PKG_RELEASE=$(PKG_SOURCE_VERSION)
 
 PKG_SOURCE_PROTO:=git
 PKG_SOURCE_URL=$(OPENWRT_GIT)/project/fstools.git
 PKG_SOURCE_SUBDIR:=$(PKG_NAME)-$(PKG_VERSION)
-PKG_SOURCE_VERSION:=ed224f0b1f9cfb3f8c5766cba3a60343c0eda586
+PKG_SOURCE_VERSION:=db5d39d48b9d9a77565015c1aafb3ef0d2925f02
 PKG_SOURCE:=$(PKG_NAME)-$(PKG_VERSION)-$(PKG_SOURCE_VERSION).tar.gz
 CMAKE_INSTALL:=1