wininet: Don't leak the proxy username and password in WININET_SetProxyAuthorization.
diff --git a/dlls/wininet/dialogs.c b/dlls/wininet/dialogs.c
index 4a4df92..2235d85 100644
--- a/dlls/wininet/dialogs.c
+++ b/dlls/wininet/dialogs.c
@@ -231,12 +231,14 @@
     if( !p )
         goto done;
 
+    HeapFree(GetProcessHeap(), 0, hIC->lpszProxyUsername);
     hIC->lpszProxyUsername = p;
 
     p = heap_strdupW(password);
     if( !p )
         goto done;
 
+    HeapFree(GetProcessHeap(), 0, hIC->lpszProxyPassword);
     hIC->lpszProxyPassword = p;
 
     ret = TRUE;