multimedia/kodi: update to 17.3 (bugfix)

• Update kodi to 1.7.3
• Unregister CONFLICTS_BUILD because it was fixed in r440033

Changes: https://kodi.tv/article/kodi-v173-minor-bug-fix-and-security-release

PR: 220603
Submitted by: Mikael Urankar <mikael.urankar@gmail.com> (maintainer)
MFH: 2017Q3