aaargh

svn path=/trunk/mcs/; revision=23009

mcs/class/System/System.Net/BasicClient.cs

@@ -18,7 +18,7 @@ namespace System.Net
 				return null;
 
 			string header = challenge.Trim ();
-			if (!header.ToLower ().IndexOf ("basic"))
+			if (header.ToLower ().IndexOf ("basic") == -1)
 				return null;
 
 			return InternalAuthenticate (webRequest, credentials);

mcs/class/System/System.Net/DigestClient.cs

@@ -334,7 +334,7 @@ namespace System.Net
 				return null;
 	
 			string header = challenge.Trim ();
-			if (!header.ToLower ().IndexOf ("digest"))
+			if (header.ToLower ().IndexOf ("digest") == -1)
 				return null;
 
 			HttpWebRequest request = webRequest as HttpWebRequest;