Enhacements to crash mining tool V.II

* Do not try backup apport configuration when running with gdb
* Adding Package version and distro release version to duplicate note in tracker
* Reopen an issue when a duplicate is found.
    * Configurable via `crash-digger.conf`file
I'd prefer smt like:

    from collections import Iterable
    isinstance(self.status['closed'], Iterable)

but doesn't really matter