JBEHAVE-1076: update travis config to leverage the container-based infrastructure
JBEHAVE-1076: update travis config to leverage the container-based infrastructure

Customizations are not needed anymore: mvn 3.2.5 is installed by default.

codehaus/jbehave-core,codehaus/jbehave-core,codehaus/jbehave-core,codehaus/jbehave-core,codehaus/jbehave-core