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
vold: fix crash for non-emulated primary storage

When EMULATED_STORAGE_SOURCE is not set, emulated_source
will be null

Change-Id: I22d040eda498d4c2a5becd367eb5b9a55a494e0b
Merge "vold: restore 4.4 sdcard logic" into cm-11.0
vold: mount ext4 with forced SELinux context

Always mount voldmanaged ext4 partitions with the SELinux sdcard_external
context. For other file systems, this is done via the genfs_context,
but since ext4 supports SELinux natively, it must be set here.

Change-Id: I1364f37018b25d79b1826c85849def64e868d72f
vold: force SELinux context only for sdcard

Google uses this code to mount ASEC as well and we shouldn't force
their SELinux contexts

Change-Id: I873af4dc2309d3d0942ce466b8acf8158abb85ae
Merge remote-tracking branch 'cm/cm-11.0' into HEAD