Fix mounting /sdcard under recovery.

The CL in [1] changed to create a symlink to /storage/self/primary for
/sdcard. It breaks the mount of /sdcard under recovery.

[1] commit 595003a3d06a13862052ef2f4f578371dae5ad65

Bug: 26509280
Change-Id: I98d02d54d707c2c8826c5ee119cf1a3ffa0c4bc9
1 file changed