base: fix external sdcard mountpoint

It needs to add that line on init.xxxx.rc on rootdir folders.

"chown root root /mnt/media_rw"

Needed for devices that has some troubles mounting storages.

Credits: http://forum.xda-developers.com/showthread.php?t=2537793

Change-Id: I0c9e2ae5439c8d8a762904e2760eb6590ce77a62
Make "SD Card removed" notification dismissible if the removed SD Card is not the primary storage

The Galaxy S uses the "external SD Card" as the extended storage
and it the notification should be dismissible as it's okay not
to have it.

Additionally, this patch also not hide the USB storage mount dialog
if the removed storage is not the primary storage

Adapted for CM 11

Change-Id: Ic752a3da917e0d7736a619fb68f07905106987fb