*) mod_setenvif: We can have expressions that become true if a regex pattern

   in the expression does NOT match. In this case val is NULL
   and we should just set the value for the environment variable
   like in the pattern case.
+1: jailletc36, jim, minfrin


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/2.4.x@1847292 13f79535-47bb-0310-9956-ffa450edef68