Add migration to quote encrypted image location urls

Migration 015_quote_swift_credentials.py failed to take into account
encrypted location values. This patch adds a similar migration
that if the value is encrypted then:
1. Decrypts the value
2. Quotes the url string
3. Encrypts the value
4. Inserts back into DB

fixes bug 1081043

Change-Id: Iadfe5f5082b3932307eef8e76571e36c6ff9fce7
Merge "Add migration to quote encrypted image location urls"