Backport: r1546860

Submitted by: jailletc36
Fix missing space in message of protocol.c (other r1546860 changes ignored)


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x-merge-http-strict@1768968 13f79535-47bb-0310-9956-ffa450edef68