cubicweb #1725690 synchronization lock on datafeed source [resolved]

to ensure we don't have concurrent updates we'ld probably mess up together

prioritynormal
typeenhancement
done in3.13.0
load1.000
load left0.000
closed by#c54038622fc9 [datafeed] use a boolean flag on CWSource to ensure we don't have concurrent synchronizations. Closes #1725690