Remove some redundant fields

These were getting out of sync and causing trouble, and they are easy to
compute from existing information.

Fixes some problems detected by the testsuite where the user/password or
the host would sometime disappear from the URL.

headers/os/net/Url.h

@@ -89,6 +89,8 @@ public:
 private:
 			void				_ResetFields();
 			void				_ExplodeUrlString(const BString& urlString);
+			BString				_MergePath(const BString& relative) const;
+			void				_SetPathUnsafe(const BString& path);
 
 	static	BString				_DoUrlEncodeChunk(const BString& chunk, 
 									bool strict, bool directory = false);
@@ -121,10 +123,8 @@ private:
 			bool				fHasProtocol : 1;
 			bool				fHasUserName : 1;
 			bool				fHasPassword : 1;
-			bool				fHasUserInfo : 1;
 			bool				fHasHost : 1;
 			bool				fHasPort : 1;
-			bool				fHasAuthority : 1;
 			bool				fHasPath : 1;
 			bool				fHasRequest : 1;
 			bool				fHasFragment : 1;