Use standard open command in fasd and lighthouse plugins

plugins/fasd/fasd.plugin.zsh

@@ -5,7 +5,7 @@ if [ $commands[fasd] ]; then # check if fasd is installed
   fi
   source "$fasd_cache"
   unset fasd_cache
-  alias v='f -e vim'
-  alias o='a -e open'
-fi
 
+  alias v='f -e vim'
+  alias o='a -e open_command'
+fi

plugins/lighthouse/lighthouse.plugin.zsh

@@ -9,7 +9,7 @@ open_lighthouse_ticket () {
   else
     lighthouse_url=$(cat .lighthouse-url);
     echo "Opening ticket #$1";
-    `open $lighthouse_url/tickets/$1`;
+    open_command "$lighthouse_url/tickets/$1";
   fi
 }