CID 1435130: Incorrect expression (COPY_PASTE_ERROR)

Seems like legacy/trac#23693 (moved) caused the following coverity warning:

** CID 1435130:  Incorrect expression  (COPY_PASTE_ERROR)
/src/or/router.c: 153 in dup_onion_keys()

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*** CID 1435130:  Incorrect expression  (COPY_PASTE_ERROR)
/src/or/router.c: 153 in dup_onion_keys()
147       tor_assert(key);
148       tor_assert(last);
149       tor_mutex_acquire(key_lock);
150       if (onionkey)
151         *key = crypto_pk_copy_full(onionkey);
152       else
>>>     CID 1435130:  Incorrect expression  (COPY_PASTE_ERROR)
>>>     "last" in "*last = NULL" looks like a copy-paste error.
153         *last = NULL;
154       if (lastonionkey)
155         *last = crypto_pk_copy_full(lastonionkey);
156       else
157         *last = NULL;
158       tor_mutex_release(key_lock);

Perhaps this new *last = NULL; should have been *key = NULL.