Get rid of a warning in the HipChat plugin

Dependencies

• [2] ZDEHAFHV Add a plugin for HipChat notification
• [3] NB2VOKIR Include names of committers in HipChat notifications

Change contents

• replacement in src/lib/Hydra/Plugin/HipChatNotification.pm at line 12
  [2.293]→[2.293:348](∅→∅)
  − my @config = ref $cfg eq "ARRAY" ? @$cfg : ($cfg);
  [2.293]

  [2.348]
  + my @config = defined $cfg ? ref $cfg eq "ARRAY" ? @$cfg : ($cfg) : ();