Win32: Use the COMSPEC envar to set the shell name.

Submitted by:	Bill Rowe <wrowe@Ind.com>
Reviewed by:	Bill Stoddard <stoddard@apache.org>


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@84702 13f79535-47bb-0310-9956-ffa450edef68