Fix bug3 13933442 Search - for security reasons only index data...

...from wellknown SearchIndexablesProvider

Check if the SearchIndexablesProvider is:

- having the correct android.permission.READ_SEARCH_INDEXABLES
read/write permissions
- a privileged one (like Settings App, Phone App)

Change-Id: I5fd1fef46716cca0e439196e24b607ff5506495c