Stops the loop when all files are closed.

The CL changes FuseBridgeLoop so that it exits when all files opened on
the AppFuse mount point are closed. Note that the client code will
unmount the FUSE mount point after the loop exits.

Bug: 32260320
Test: libappfuse_test
Change-Id: I4965fbb48de8a280c6306e70757a07376b1956a7
2 files changed