D18947: Bring FindUDev.cmake up to ECM standards

[Christophe Giboudeaux]

cgiboudeaux accepted this revision.

REPOSITORY
  R245 Solid

BRANCH
  arcpatch-D18947

REVISION DETAIL
  https://phabricator.kde.org/D18947

To: vkrause, #build_system, cgiboudeaux, apol
Cc: aacid, apol, kde-frameworks-devel, michaelh, ngraham, bruns