Travis: do not run the tests if building Coq fails
Travis: do not run the tests if building Coq fails

SkySkimmer/coq,letouzey/coq-wip,gares/coq,coq/coq,Zimmi48/coq,ppedrot/coq,ppedrot/coq,maximedenes/coq,JasonGross/coq,ejgallego/coq,silene/coq,Zimmi48/coq,gares/coq,JasonGross/coq,amintimany/coq,william-lawvere/coq,gares/coq,letouzey/coq-wip,william-lawvere/coq,Lionel-Rieg/coq,SkySkimmer/coq,silene/coq,Lionel-Rieg/coq,ejgallego/coq,JasonGross/coq,ejgallego/coq,SkySkimmer/coq,Zimmi48/coq,letouzey/coq-wip,ppedrot/coq,Lionel-Rieg/coq,william-lawvere/coq,letouzey/coq-wip,ppedrot/coq,coq/coq,amintimany/coq,letouzey/coq-wip,gares/coq,Zimmi48/coq,ejgallego/coq,coq/coq,Matafou/coq,ppedrot/coq,amintimany/coq,JasonGross/coq,Matafou/coq,maximedenes/coq,gares/coq,SkySkimmer/coq,maximedenes/coq,Matafou/coq,maximedenes/coq,silene/coq,maximedenes/coq,coq/coq