Add support for esdfs mounting

If sdcardfs is turned off, try mounting esdfs.

Test: Override ro.sys.sdcardfs to be false, or run
      sm set-sdcardfs off. If the kernel contains
      esdfs, it will use it.
Bug: 63876697
Change-Id: I4db8bf336743edf62edfae41d753b1e3af163950