repair: define explicit local variable, don't reuse a comprehension variable

The node ID used in strip bundle names is currently taken as the last
iterated value in a list comprehension found much earlier in the function.
This change makes the node selection more explicit at the cost of redundancy.

mercurial/repair.py

@@ -137,6 +137,7 b' def strip(ui, repo, nodelist, backup=Tru'
     # create a changegroup for all the branches we need to keep
     backupfile = None
     vfs = repo.vfs
+    node = nodelist[-1]
     if backup:
         backupfile = _bundle(repo, stripbases, cl.heads(), node, topic)
         repo.ui.status(_("saved backup bundle to %s\n") %