Are you using the flash web client or the HTML 5?
/etc/vmware/vsphere-client/vc-packages/vsphere-client-serenity is the path for the flash client
The correct path for the H5 client is /etc/vmware/vsphere-ui/vc-packages/vsphere-client-serenity/
However this is a moot point as the plugin is not registered in vc-packages as it is only a redirect to the html 5 server on the SRM server.
you should find traces of the redirect in:
with a filename of:
with a folder:
with a file:
We can fix the icon in the webclient later; first try access the web server on the SRM box via the following URL and see if you can manage SRM:
https://<SRM server FQDN or IP>/dr/
It should redirect you to a login screen on the PSC then flip back to the SRM server and show you the GUI.
If that is working then we know that your SRM install is functional we can then sort out the plugin icon
Let me know!