Never exit directly from commands.dispatch(), but pass return code to caller. Usually the caller is commands.run(). Some extensions still use sys.exit(), this is catched, too. Fixed wrong return statement in commands.recover() yielding a zero exit code.

abort: repository a not found!
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requesting all changes
abort: error: Connection refused
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abort: repository a not found!
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abort: destination '../a' already exists
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abort: repository a not found!
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abort: destination 'q' already exists