Fix problem with chunking and bputc().

Don't use large_write() when nbytes == 1... otherwise we have really bad
performance at end of buffer with bputc().

Reviewed by:	Rasmus Lerdorf, Jim Jagielski


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@79783 13f79535-47bb-0310-9956-ffa450edef68