Clean up capinfos output.

Make sure there's always a space between a number and "[TGMK]bytes",
"[TGMK]bits", and "[TGMK]packets".

Change-Id: I710385303e451e9aea6fc9bbea562f59ca0d22c9
Reviewed-on: https://code.wireshark.org/review/3810
Reviewed-by: Guy Harris <guy@alum.mit.edu>