Bug 613679 - pluginreg.dat rewritten on plugins list construction, even if there are no changes, r=josh, a=josh

modules/plugin/base/src/nsPluginHost.cpp

@@ -2143,8 +2143,10 @@ nsresult nsPluginHost::ScanPluginsDirectory(nsIFile * pluginsDir,
 
     // do it if we still want it
     if (bAddIt) {
-      // We have a valid new plugin so report that plugins have changed.
-      *aPluginsChanged = PR_TRUE;
+      if (!seenBefore) {
+        // We have a valid new plugin so report that plugins have changed.
+        *aPluginsChanged = PR_TRUE;
+      }
 
       // If we're not creating a plugin list, simply looking for changes,
       // then we're done.