Increase connection negotiation timeout
  Improve some weirdness


storage/ndb/src/common/transporter/Transporter.cpp:
  - Increase connection negotiation timeout
  - return false if trying to connect when already connected (should still be assert)
storage/ndb/src/common/transporter/TransporterRegistry.cpp:
  Use correct "is_connected" checks
    (although this is kind of bogus and should be cleaned-up)