Fix prompt call, close #22

init.zsh

@@ -88,7 +88,11 @@ autoload -Uz promptinit && promptinit
 
 # Load the prompt theme.
 zstyle -a ':omz:prompt' theme 'prompt_argv'
-prompt "$prompt_argv[@]"
+if (( $#prompt_argv > 0 )); then
+  prompt "$prompt_argv[@]"
+else
+  prompt 'off'
+fi
 unset prompt_argv
 
 # Compile the completion dump, to increase startup speed.