The specs deleted a global authorizations:* pattern from the shared
test Redis DB, so concurrent test processes could wipe each other's
keys mid-example, causing intermittent empty/mismatched set failures.
Drop all global pattern deletes and the now-unused
redis_rs_delete_keys helper. Each spec now reads or asserts only the
exact key derived from its own random token, so runs can no longer
interfere regardless of ordering or concurrency.
Also fixes a vacuous assertion in the #destroy spec, which checked
authorizations:<user.address>:* (never matching the keys, which use
user.cn), to assert the exact key is gone.
raucao