logger: Don't store verbose-magic in the log files.

In r399267, the verbose2magic stuff was edited. This time it results
in magic characters in the log files for multiline messages.

In trunk (and 13) this was fixed by the "stripping" of those
characters from multiline messages (in r414798).

This is a backport of that fix to 11. That fix is altered to actually
strip the characters and not replace them with blanks.

Review: https://reviewboard.asterisk.org/r/3901/
Review: https://reviewboard.asterisk.org/r/3902/
........

Merged revisions 420897 from http://svn.asterisk.org/svn/asterisk/branches/11


git-svn-id: http://svn.asterisk.org/svn/asterisk/branches/12@420898 f38db490-d61c-443f-a65b-d21fe96a405b