.travis.yml: Do not use Clang as it does not work with C++11 well. Prune the tests configurations.
.travis.yml: Do not use Clang as it does not work with C++11 well.
Prune the tests configurations.

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