Fix security hole with "UserDir /a/b" without a * in the path... you

could request /~../ and get /a.

(djg: I also did a few touches of cleanup.)

PR:		1701
Submitted by:	Lauri Jesmin <jesmin@ut.ee>
Reviewed by:	Marc Slemko, Dean Gaudet


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/branches/1.3.x@80205 13f79535-47bb-0310-9956-ffa450edef68