If url is relative, use session.url (...) to get valid url.

It could happen with relative url in `Location: ...` header (for redirection).

library/network/http_client/src/http_client_request.e

@@ -31,7 +31,11 @@ feature {NONE} -- Initialization
 			-- This can be used to reset/reinitialize Current with new url
 			-- in the case of redirection.
 		do
-			url := a_url
+			if a_url.starts_with ("http://") or a_url.starts_with ("http://") then
+				url := a_url
+			else
+				url := session.url (a_url, Void)
+			end			
 			headers := session.headers.twin
 			if ctx /= Void then
 				context := ctx

library/network/http_client/src/spec/net/net_http_client_request.e

@@ -113,6 +113,7 @@ feature -- Access
 					-- Get URL data
 				l_is_https := url.starts_with_general ("https://")
 				create l_uri.make_from_string (url)
+				check valid_url: l_uri.is_valid end				
 				l_port := l_uri.port
 				if l_port = 0 then
 					if l_is_https then