Fix gotmode() regression

[michaelortmann]

Found by: https://github.com/crazycatdevs
Patch by: https://github.com/michaelortmann
Fixes: #1861

One-line summary:
Fix gotmode() regression

Additional description (if needed):
See #1861

Test cases demonstrating functionality (if applicable):
/mode #testchan +vv testuser1 testuser2
Before:

[21:40:19] [@] :michael!~michael@localhost MODE #testchan +vv testuser1 testuser2
[21:40:19] #testchan: mode change '+vv testuser1' by michael!~michael@localhost
[21:40:19] * Mode change on #testchan for nonexistent !

After:

[21:59:58] [@] :michael!~michael@localhost MODE #testchan +vv testuser1 testuser2
[21:59:58] #testchan: mode change '+vv testuser1 testuser2' by michael!~michael@localhost

[crazycatdevs]

Tested on the same bot than previously, no more error message