urldata: don't touch data->set.httpversion at run-time

Rename it to 'httpwant' and make a cloned field in the state struct as
well for run-time updates.

Also: refuse non-supported HTTP versions. Verified with test 129.

Closes #6585

tests/data/test129

@@ -0,0 +1,57 @@
+<testcase>
+<info>
+<keywords>
+HTTP
+HTTP GET
+</keywords>
+</info>
+
+#
+# Server-side
+<reply>
+<data nocheck="yes">
+HTTP/1.2 200 OK
+Date: Tue, 09 Nov 2010 14:49:00 GMT
+Server: test-server/fake
+Last-Modified: Tue, 13 Jun 2000 12:10:00 GMT
+ETag: "21025-dc7-39462498"
+Accept-Ranges: bytes
+Content-Length: 6
+Connection: close
+Content-Type: text/html
+Funny-head: yesyes
+
+-foo-
+</data>
+</reply>
+
+#
+# Client-side
+<client>
+<server>
+http
+</server>
+ <name>
+HTTP/1.2 is rejected
+ </name>
+ <command>
+http://%HOSTIP:%HTTPPORT/129
+</command>
+</client>
+
+#
+# Verify data after the test has been "shot"
+<verify>
+<protocol>
+GET /129 HTTP/1.1
+Host: %HOSTIP:%HTTPPORT
+User-Agent: curl/%VERSION
+Accept: */*
+
+</protocol>
+# CURLE_UNSUPPORTED_PROTOCOL
+<errorcode>
+1
+</errorcode>
+</verify>
+</testcase>