.travis.yml: Provide and use GCC 4.8.
.travis.yml: Provide and use GCC 4.8.

csuideal/log4cplus,ccpaging/log4cplus,csuideal/log4cplus,ccpaging/log4cplus,ccpaging/log4cplus,ccpaging/log4cplus,csuideal/log4cplus,csuideal/log4cplus