Bump Travis timeout. It's still too low, e.g.,
Bump Travis timeout. It's still too low, e.g.,

https://travis-ci.org/google/guava/builds/161636738

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mosoft521/guava,typetools/guava,rgoldberg/guava,rgoldberg/guava,berndhopp/guava,google/guava,EdwardLee03/guava,Xaerxess/guava,DavesMan/guava,tli2/guava,tli2/guava,google/guava,mosoft521/guava,google/guava,xasx/guava,mosoft521/guava,xasx/guava,berndhopp/guava,Xaerxess/guava,DavesMan/guava,EdwardLee03/guava,typetools/guava