cubicweb-vcsfile #2189200 VersionContent should store HG rev ID, not revision numbers [done]

Keeping revision number is the assurance that stored data will soon be inconsistent...

priorityimportant
typebug
done in1.9.4
load1.000
load left0.000
closed by#69942eb3dbe0 VCSStorage: store the changeset number instead of the revnum for mercurial