rebase: refactoring to avoid repetition of expression

This patch removes the repetition of "(revignored, revprecursor, revpruned)"
and replaces its occurences with the more legible "revskipped".

hgext/rebase.py

@@ -34,6 +34,7 b' revignored = -3'
 revprecursor = -4
 # plain prune (no successor)
 revpruned = -5
+revskipped = (revignored, revprecursor, revpruned)
 
 cmdtable = {}
 command = cmdutil.command(cmdtable)
@@ -681,7 +682,7 b' def defineparents(repo, rev, target, sta'
     elif p1n in state:
         if state[p1n] == nullmerge:
             p1 = target
-        elif state[p1n] in (revignored, revprecursor, revpruned):
+        elif state[p1n] in revskipped:
             p1 = nearestrebased(repo, p1n, state)
             if p1 is None:
                 p1 = target
@@ -697,7 +698,7 b' def defineparents(repo, rev, target, sta'
         if p2n in state:
             if p1 == target: # p1n in targetancestors or external
                 p1 = state[p2n]
-            elif state[p2n] in (revignored, revprecursor, revpruned):
+            elif state[p2n] in revskipped:
                 p2 = nearestrebased(repo, p2n, state)
                 if p2 is None:
                     # no ancestors rebased yet, detach