Log Message:
xfce4-panel: update to 4.14.4

Change log:

4.14.4
======
- Fix panel build with vala 0.48 (Bug #16426)
- Fix memory leak in panel plugin wrapper (Bug #16640)
- tasklist: Fix crash middle-click-closing grouped windows (Bug #16410)
- panel: Make sure "span monitors" is conditionally sensitive
  (Bug #15169)
- Translation Updates:
  Albanian, Amharic, Arabic, Armenian (Armenia), Belarusian, Bengali,
  Catalan, Chinese (China), Chinese (Hong Kong), Croatian, Czech, Danish,
  Dutch, English (Australia), Estonian, Finnish, French, Galician,
  Georgian, Hebrew, Hungarian, Icelandic, Indonesian, Italian, Japanese,
  Kazakh, Malay, Norwegian Bokmål, Norwegian Nynorsk, Occitan (post
  1500), Panjabi (Punjabi), Portuguese, Romanian, Sinhala, Swedish, Thai,
  Uighur, Ukrainian, Vietnamese