vold: add support for ext4 media

Squashed commit of the following:

Author: codeworkx <codeworkx@cyanogenmod.org>
vold: add support for ext4 media

Depends on:
http://review.cyanogenmod.org/31202
http://review.cyanogenmod.org/31211

Result:
http://pastebin.com/nzUbvW7K
Change-Id: I5bd227e637f2a1ed4d13a2eb81390c56c953f482

Author: Ricardo Cerqueira <cyanogenmod@cerqueira.org>
vold: Replace usage of discontinued logwrap()
Change-Id: Ia76bf8998064beee5e0ea4451c4dd8418c2193c4

Author: Ricardo Cerqueira <cyanogenmod@cerqueira.org>
Apply the mounts to the SDCARD /storage path instead of /mnt/media_rw
Change-Id: I6c8d73a00c6ffa64875f3c4c718d8a416d08d5c1

Author: Pawit Pornkitprasan <p.pawit@gmail.com>
vold: restore 4.4 sdcard logic

Mount points in 4.4 are always fuse-wrapped to provide granular
permission. Unix file systems no longer need to be manually
fuse-wrapped by us.
Change-Id: I6885b0baeaae7c380ec32d410a70a4f53801157b

Change-Id: I5bd227e637f2a1ed4d13a2eb81390c56c953f482