Update .travis.yml
Update .travis.yml

Disable clang (compilation is fine, but one unit test is failing, investigation is required)
openMVG/openMVG,poparteu/openMVG,Vinzza/openMVG,poparteu/openMVG,Vinzza/openMVG,Smozeley/openMVG,yoshidaken/openMVG,danylaksono/openMVG,poparteu/openMVG,yoshidaken/openMVG,danylaksono/openMVG,mojovski/openMVG,Smozeley/openMVG,caymard/openMVG,Vinzza/openMVG,poparteu/openMVG,yoshidaken/openMVG,caymard/openMVG,danylaksono/openMVG,openMVG/openMVG,openMVG/openMVG,openMVG/openMVG,mojovski/openMVG,openMVG/openMVG,Smozeley/openMVG,caymard/openMVG,mojovski/openMVG