cubicweb-email #2515092 Email.references() method is faulty [validation pending]

The References header may store a space-separated list of values, which is not correctly handled by Email.references() (entities.py)

prioritynormal
typebug
done in1.9.0
load0.250
load left0.000
closed by#277d815fe802 [entities] fix references method (closes #2515092)