Simplify btos()

[michaelortmann]

Found by: michaelortmann
Patch by: michaelortmann
Fixes:

One-line summary:
Simplify btos()

Additional description (if needed):
Also makes static analyzers like scan-build happy

Test cases demonstrating functionality (if applicable):

.traffic
[14:42:04] tcl: builtin dcc call: *dcc:traffic -HQ 1 
Traffic since last restart
==========================
IRC:
  out: 291 Bytes (291 Bytes today)
   in: 4.24 KBytes (4.24 KBytes today)
Partyline:
  out: 0 Bytes (0 Bytes today)
   in: 9 Bytes (9 Bytes today)
---
Total:
  out: 291 Bytes (291 Bytes today)
   in: 4.25 KBytes (4.25 KBytes today)
[14:42:04] #-HQ# traffic