CORE-4239 Restored panelError background color.

Reverted panelError background color to iplant-orange, added in 64b1090531e4b8c206c130bb8a80aa14d6977c37.
Changed the panelError border to white, to conform with the improvements added in c7e3e48cfc58a398399e6a3cc4041575f502d59f.