Make sure that z_RC is not Z_STREAM_END in case we get a 0-length bucket

and we don't enter the while loop.

Submitted by:	Jeff Trawick's horde of picky compilers


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@95359 13f79535-47bb-0310-9956-ffa450edef68