For applying update from SD card, we used to use a thread to serve the
file with fuse. Since accessing through fuse involves going from kernel
to userspace to kernel, it may run into deadlock (e.g. for mmap_sem)
when a page fault occurs. Switch to using a process instead.
Bug: 23783099
Bug: 26313124
Change-Id: Iac0f55b1bdb078cadb520cfe1133e70fbb26eadd
Make a fuse filesystem that sits on top of the selected package file
on the sdcard, so we can verify that the file contents don't change
while being read and avoid copying the file to /tmp (that is, RAM)
before verifying and installing it.
Change-Id: Ifd982aa68bfe469eda5f839042648654bf7386a1
