[fix bug 1155623] Change error message in skills validation.
[fix bug 1155623] Change error message in skills validation.

* Minor PEP8 fixes.

fxa90id/mozillians,akarki15/mozillians,akatsoulas/mozillians,justinpotts/mozillians,mozilla/mozillians,justinpotts/mozillians,akarki15/mozillians,chirilo/mozillians,mozilla/mozillians,johngian/mozillians,johngian/mozillians,justinpotts/mozillians,chirilo/mozillians,brian-yang/mozillians,brian-yang/mozillians,fxa90id/mozillians,anistark/mozillians,brian-yang/mozillians,akatsoulas/mozillians,safwanrahman/mozillians,safwanrahman/mozillians,mozilla/mozillians,anistark/mozillians,hoosteeno/mozillians,johngian/mozillians,chirilo/mozillians,safwanrahman/mozillians,akarki15/mozillians,akatsoulas/mozillians,fxa90id/mozillians,akatsoulas/mozillians,anistark/mozillians,anistark/mozillians,mozilla/mozillians,akarki15/mozillians,johngian/mozillians,chirilo/mozillians,brian-yang/mozillians,hoosteeno/mozillians,hoosteeno/mozillians,hoosteeno/mozillians,safwanrahman/mozillians,justinpotts/mozillians,fxa90id/mozillians