Eliminate can_delete_db

The method can_delete_db() appears to be not only unused, but has
always been so. I verified this going back to Austin release. It is
very strange that we never noticed it until now, but here it is.

Change-Id: I4445c4b2c4721f880c9dbb1eac055c0601ae6372
Merge "Eliminate can_delete_db"