rebase: make dry-run return 1 or 0 according to result

In dry-run mode, if there is no conflict return 0, if any then return 1

Differential Revision: https://phab.mercurial-scm.org/D3829

hgext/rebase.py

@@ -825,8 +825,10 b' def rebase(ui, repo, **opts):'
                             **opts)
         except error.InMemoryMergeConflictsError:
             ui.status(_('hit a merge conflict\n'))
+            return 1
         else:
             ui.status(_('there will be no conflict, you can rebase\n'))
+            return 0
         finally:
             _origrebase(ui, repo, abort=True)
     elif inmemory:

tests/test-rebase-inmemory.t

@@ -287,6 +287,7 b' Make a conflict:'
   rollback completed
   hit a merge conflict
   rebase aborted
+  [1]
   $ hg diff
   $ hg status
   $ hg log -G --template "{rev}:{short(node)} {person(author)}\n{firstline(desc)} {topic}\n\n"
@@ -322,3 +323,4 b' Check dryrun working with --collapse whe'
   merging e
   hit a merge conflict
   rebase aborted
+  [1]