travis-ci: If make check fails, cat the test-suite.log files
travis-ci: If make check fails, cat the test-suite.log files

This should help with finding the actual causes of test suite failures
during travis-ci checks.

gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2,gphoto/libgphoto2