cubicweb-conference #490875 past conferences [resolved]

Text for primary views of /conference and /track should not be using the future tense if the conference is over (and in the past).

prioritynormal
typebug
done in0.2.0
load0.100
load left0.000
closed by#efef74f13b32 Tense of sentences depends on current date (closes #490875)