Always symlink self/primary to /storage/emulated

This allows readlink(2) of /sdcard paths to work correctly
and return /storage/emulated/<userid> instead of
/mnt/user/<userid>/emulated/<userid>

Test: readlink /sdcard -> /storage/emulated/0
Bug: 135341433
Change-Id: I2cfa9cede02a93024e41d90f17c926a69ec6e052
1 file changed