Take persistable uri permission for document provider

ACTION_GET_CONTENT is to simply read/import data.ACTION_OPEN_DOCUMENT
is to have long term, persistent access to documents owned by a
document provider. When user select music as alarm ringtone from
external storage, the music file is possible to be a document provider
file. DeskClock will lose access to document provider file after reboot.
DeskClock need long term, persistent access to documents owned by
document provider. So Take persistable uri permission for document
provider.

Change-Id: I110873d4c49eed34d9cabc8bd457e12eba9ced1f
CRs-Fixed: 1046238