cubicweb-vcsfile #5270275 VCSInclude directive should catch hglib errors [validation pending]

if the local repo is not uptodate (or not there) we shouldn't get a traceback into the log, an error in the rendered html is enough

prioritynormal
typebug
done in2.1.0
load0.500
load left0.000
closed by#984d889e5464 [rest] catch more errors from hglib (closes #5270275)
patch[rest] catch more errors from hglib (closes #5270275) [applied]