Fix copy-paste error that referred to the wrong variable.
Bug found by David Binderman.


git-svn-id: svn://svn.code.sf.net/p/tigervnc/code/trunk@5126 3789f03b-4d11-0410-bbf8-ca57d06f2519
diff --git a/vncviewer/parameters.cxx b/vncviewer/parameters.cxx
index 6c2af38..68ddee1 100644
--- a/vncviewer/parameters.cxx
+++ b/vncviewer/parameters.cxx
@@ -523,8 +523,8 @@
   /* Write parameters to file */
   FILE* f = fopen(filepath, "w+");
   if (!f) {
-    snprintf(write_error, sizeof(filepath), "Failed to write configuration file, "
-	     "can't open %s", filepath);
+    snprintf(write_error, sizeof(write_error),
+             "Failed to write configuration file, can't open %s", filepath);
     throw Exception(write_error);
   }