Mirror node-canvas' .travis.yml to fix build errors.
Mirror node-canvas' .travis.yml to fix build errors.

seyfert/vega,vega/vega,seyfert/vega,lgrammel/vega,nyurik/vega,nyurik/vega,seyfert/vega,vega/vega,vega/vega,nyurik/vega,timelyportfolio/vega,timelyportfolio/vega,vega/vega