tweak firefox upgrade instructions

pavelib/utils/test/utils.py

@@ -73,8 +73,9 @@ def check_firefox_version():
         raise Exception(
             'Required firefox version not found.\n'
             'Expected: {expected_version}; Actual: {actual_version}.\n\n'
-            'As the root user in devstack, run the following:\n\n'
+            'As the vagrant user in devstack, run the following:\n\n'
             '\t$ sudo wget -O /tmp/firefox_28.deb https://s3.amazonaws.com/vagrant.testeng.edx.org/firefox_28.0%2Bbuild2-0ubuntu0.12.04.1_amd64.deb\n'
+            '\t$ sudo apt-get remove firefox\n\n'
             '\t$ sudo gdebi -nq /tmp/firefox_28.deb\n\n'
             'Confirm the new version:\n'
             '\t$ firefox --version\n'