Revert "Fixes +2918. Invoke installer when wrong tmux version is installed"
Revert "Fixes +2918. Invoke installer when wrong tmux version is installed"

This reverts commit 1c8aa95808c576a782f736c3ff6f49b7dbb6af52.
GHackAnonymous/c9.ide.installer,c9/c9.ide.installer,c9/c9.ide.installer,GHackAnonymous/c9.ide.installer,GHackAnonymous/c9.ide.installer,c9/c9.ide.installer