mod_proxy_{ajp,fcgi}: Fix a possible crash when reusing an established

backend connection, happening with LogLevel trace2 or higher configured,
or at any log level with compilers not detected as C99 compliant (e.g.
MSVC on Windows).



git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1775775 13f79535-47bb-0310-9956-ffa450edef68