Clean up travis config in 0.29.x branch.
Clean up travis config in 0.29.x branch.

cython/cython,cython/cython,da-woods/cython,scoder/cython,cython/cython,cython/cython,scoder/cython,da-woods/cython,da-woods/cython,scoder/cython,da-woods/cython,scoder/cython