Add case_preserved_filename field to the request_rec structure.

On systems with case insensitive file systems (Windows, OS/2, etc.),
r->filename is case canonicalized (folded to either lower or upper
case, depending on the specific system) to accomodate file access
checking. case_preserved_filename is the same as r->filename
except case is preserved. There is at least one instance where Apache
needs access to the case preserved filename: Java class files published
with WebDAV need to preserve filename case to make the Java compiler
happy.


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@84804 13f79535-47bb-0310-9956-ffa450edef68