Exclude Qt warnings on clang dashboards.

Change-Id: I52589e1206c681f44670f7a3547c956f14019b06
Merge topic 'clang_warnings' into next

812e45d4 Exclude Qt warnings on clang dashboards.
nektar: disable metis warnings completely

Change-Id: I96f4f01add3b2d2beb2e6ce87a4599c2776beecb
Merge topic 'nektar-flag-warning' into next

24a6d340 nektar: disable metis warnings completely