Change HttpProtocol to again only allow to enable/disable 0.9

    
This reverts r1407643, but changes the syntax of HttpProtocol to
min=0.9|1.0, which is less ambiguous than the previous +0.9|-0.9.
    
Allowing to configure an arbitrary version range was a bad idea,
because it only checked the version in the request line, without
affecting the semantics of the headers, etc.
    
A tighter restriction off the version in the request line is still
possible with <If "%{SERVER_PROTOCOL_NUM} ..."> .


git-svn-id: https://svn.apache.org/repos/asf/httpd/httpd/trunk@1425366 13f79535-47bb-0310-9956-ffa450edef68