Unit tests for the ctdb tool (i.e. tools/ctdb).

Test case filenames can take 2 forms:

* func.<some_function>.NNN.sh

  Run <some_function> in the ctdb tool code using the
  ctdb_tool_libctdb test program.  This test program uses test stubs
  for libctdb functions.

* stubby.<command>.NNN.sh

  Run the ctdb_tool_stubby test program with <command> as the 1st
  argument - subsequent are passed to simple_test().  ctdb_tool_stubby
  is linked against the test stubs for libctdb functions.

To add tests here you may need to change commands/functions in the
ctdb tool so that they use libctdb.  You will also need to add the
appropriate test stubs.
