if setting the proxy password to blank, delete it from the keychain

macosx/Controller.m

@@ -228,7 +228,7 @@ static void sleepCallback(void * controller, io_service_t y, natural_t messageTy
                                 TR_DEFAULT_PROXY_TYPE, /* reset in prefs */
                                 [fDefaults boolForKey: @"ProxyAuthorize"],
                                 [[fDefaults stringForKey: @"ProxyUsername"] UTF8String],
-                                ""); /* reset in prefs - from Keychain (leave blank instead of NULL) */
+                                NULL); /* reset in prefs - from Keychain */
         
         [NSApp setDelegate: self];
         

macosx/EMKeychain/EMKeychainItem.h

@@ -40,6 +40,9 @@
 - (BOOL)setPassword:(NSString *)newPassword;
 - (BOOL)setUsername:(NSString *)newUsername;
 - (BOOL)setLabel:(NSString *)newLabel;
+
+//added by ML
+- (void)removeFromKeychain;
 @end 
 
 @interface EMKeychainItem (Private)

macosx/EMKeychain/EMKeychainItem.m

@@ -82,6 +82,12 @@
 	
 	return [self modifyAttributeWithTag:kSecLabelItemAttr toBeString:newLabel];
 }
+
+- (void)removeFromKeychain
+{
+    SecKeychainItemDelete(coreKeychainItem);
+}
+
 @end
 
 @implementation EMKeychainItem (Private)

macosx/PrefsController.m

@@ -757,10 +757,18 @@
     EMGenericKeychainItem * keychainItem = [[EMKeychainProxy sharedProxy] genericKeychainItemForService: @"Transmission:Proxy"
                                             withUsername: @"Proxy"];
     if (keychainItem)
+    {
+        if (![password isEqualToString: @""])
             [keychainItem setPassword: password];
         else
+            [keychainItem removeFromKeychain];
+    }
+    else
+    {
+        if (![password isEqualToString: @""])
             [[EMKeychainProxy sharedProxy] addGenericKeychainItemForService: @"Transmission:Proxy" withUsername: @"Proxy"
                 password: password];
+    }
     
     tr_sessionSetProxyPassword(fHandle, [password UTF8String]);
 }