How do I resolve git saying Commit your changes or stash them before you can merge

Question

I made some changes to my local machine and pushed it to the remote repository. I am getting this message while trying to pull the changes to the server.

error: Your local changes to the following files would be overwritten by merge:
wp-content/w3tc-config/master.php
Please, commit your changes or stash them before you can merge.

I tried solving it by running:

git checkout -- wp-content/w3tc-config/master.php

But I still get this message. I just want to merge the rest of my changes (plugin updates). I'm assuming that w3tc changed something in the config file on the server. Can someone help me with this?