cubicweb-email #9360016 mboximport crash if email contains a GPG signature [validation pending]

It uses a non existing _skipsign attribute

prioritynormal
typebug
done in1.11.1
load left0.000
closed by#4b24fd58be8b [mboximport] (re)add a --skipsign cmdline option (closes #9360016)
patch[mboximport] (re)add a --skipsign cmdline option (closes #9360016) [applied]