Mutations retried after user callback called with timeout

Libcouchbase retries mutations while it should not. To reproduce it:

1) set "foo" to "val_1"

2) suspend server (setup firewall rule to block traffic)

3) set "foo" to "val_2"

4) library reports timeout error (0x17)

5) resume server (remove firewall block)

6) get "foo"

Expected result: "val_1"
Actual result: "val_2"