Properly cleanup fresh prompt theme

If `prompt <theme>` is used, prior to this patch the `fresh_line_one`
precmd hook would not be removed. This is no longer the case and cleanup
is correctly performed.

prompt_fresh_setup

@@ -63,6 +63,12 @@ fresh_line_one() {
   # First get the last commands exit code before doing anything
   local exit_code=$?
 
+  # Clean up if fresh is no longer the current prompt theme
+  if [[ "`prompt -c | tail -1 | xargs`" != "fresh" ]]; then
+    add-zsh-hook -d precmd fresh_line_one
+    return
+  fi
+
   # Construct the time and directory portions of the prompt
   local time_stamp="%{%F{244}%}%D{%H:%M:%S}%{%f%}"
   [[ -n $SANDBOX_HOME ]] && \