Remove all unspecific except clauses

[OndrejMarsalek]

We should make sure that eventually there are no unspecific except clauses in the code base. We are not fixing all of them now, as they might go during some potential rewrites anyway. Here is a (possibly incomplete) list:

$ grep -r -n 'except:' ipi
ipi/interfaces/sockets.py:345:         except:
ipi/interfaces/sockets.py:354:      except:
ipi/interfaces/sockets.py:387:         except:
ipi/interfaces/sockets.py:411:         except:
ipi/interfaces/sockets.py:563:         except:
ipi/interfaces/sockets.py:572:      except:
ipi/interfaces/sockets.py:593:            except:
ipi/interfaces/sockets.py:721:            except:
ipi/interfaces/sockets.py:733:                  except:
ipi/utils/softexit.py:149:      except: