Escape spaces in folder name so script won't fail

If the current directory has spaces, the script fails to change paths and fails.

tools/upgrade.sh

 current_path=`pwd`
+current_path=${current_path/ /\\ }
 printf '\033[0;34m%s\033[0m\n' "Upgrading Oh My Zsh"
 cd $ZSH
 
@@ -16,4 +17,4 @@ else
   printf '\033[0;31m%s\033[0m\n' 'There was an error updating. Try again later?'
 fi
 
-cd "$current_path"
\ No newline at end of file
+cd "$current_path"