Revert "vold: use blkid to detect filesystem type"

This reverts commit 1737982971f9e6308283066e4152b276381f4274.

Change-Id: I3ddf87248f3a47d8ad403e882c803d7720c09ea1
Merge "Revert "vold: use blkid to detect filesystem type"" into illusion-4.4