Bug 1041075 - Request longer timeout for test_value_storage.html.  r=dholbert

I think this has become needed due to changes in the configuration of
the VMs on which we're running tests.

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extra : transplant_source : %83%CE%27M%CF2%0E%A9%0B%B4%9E%BC%AB%E45g%C9J%D4%17