Swift Multi-tenant store: Pass context on upload

Image upload returns an E500 as the context is not being
passed to the swift client.

Change-Id: I2065b7dd281bfbb513f13270a0c062fc7132f763
Partial-bug: 1385213
(cherry picked from commit 867b696d884e9db707683eecd321789843798efd)
Merge "Swift Multi-tenant store: Pass context on upload" into stable/juno