MINOR: log: remove the long-deprecated early log-format tags

MINOR: log: remove the long-deprecated early log-format tags

The following 10 log-format tags were implemented during log-format
development and changed before the release. They were marked as deprecated
in 2012 by commit 2beef5888 ("MEDIUM: log: change a few log tokens to make
them easier to remember") and were not documented. They've been emitting a
warning since then, with a suggestion of the one to use instead. Let's get
rid of them now.

      Bi => bi, Bp => bp, Ci => ci, Cp => cp, Fi => fi
      Fp => fp, Si => si, Sp => sp, cc => CC, cs => CS