[Fix #126] Do not evaluate undefined $git_info

Fix a bug introduced in aa0c1fa.

modules/prompt/functions/prompt_sorin_setup

@@ -45,7 +45,7 @@ function prompt_sorin_setup {
     'prompt'  ' %F{blue}git%f$(coalesce "%b" "%p" "%c")%s' \
     'rprompt' '%A%B%S%a%d%m%r%U%u'
 
-  PROMPT='%F{cyan}%1~%f${(e)git_info[prompt]} %(!.%B%F{red}#%f%b.%B%F{green}❯%f%b) '
+  PROMPT='%F{cyan}%1~%f${git_info:+${(e)git_info[prompt]}} %(!.%B%F{red}#%f%b.%B%F{green}❯%f%b) '
   RPROMPT='${editor_info[keymap]}%(?:: %F{red}⏎%f)${VIM:+" %B%F{green}V%f%b"}${git_info[rprompt]}'
   SPROMPT='zsh: correct %F{red}%R%f to %F{green}%r%f [nyae]? '
 }