fix(tools/check_for_upgrade): Don't source profile

Reverts #2296, but mostly #1883.

There is no need to source ~/.profile when this script is read. oh-my-zsh writes no configuration data in ~/.profile.

If the user wishes to use data within ~/.profile, then they should source it in another place.

Fixes #2315

tools/check_for_upgrade.sh

@@ -20,8 +20,6 @@ if [[ -z "$epoch_target" ]]; then
   epoch_target=13
 fi
 
-[ -f ~/.profile ] && source ~/.profile
-
 if [ -f ~/.zsh-update ]
 then
   . ~/.zsh-update