Make a choice when max-age is present twice

Hi,

   I got a weird bug when using Guzzle to fetch the Twitter Search API alongside a Cache mechanism.

   It appears that the Search API return twice the parameter "max-age" for the Cache Control Directives.
   Then, computing the time to cache makes Guzzle ... going crazy.

   So I propose this modification. To make an unilateral choice of the first value.
   I am not really sure if it's the best solution but I don't see any other :p 

Any thought?

Thank you

Aurélien