Fix the ap_log_error_old(), ap_log_unixerr() and ap_log_printf() functions:

First all three functions no longer fail on strings containing "%" chars and
second ap_log_printf() no longer does a double-formatting (instead it directly
passes through the message to be formatted to the real internal formatting
function).

PR: 2941


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@82021 13f79535-47bb-0310-9956-ffa450edef68