mapiproxy: Initial iplementation for more flexible mechanizm for OpenChange to crash

At the moment we few places where OpenChange just calls abort().
1. Places where we don't yet what to do - i.e. not implemented functionality
   Aborting in those situations unfortunately brakes OpenChange process.
   At the same time Samba process is running fine and it is hard for
   people to realise what is going (eg. they need to restart Samba)
2. Unexpected conditions. We certainly should abort() in such situations.
   For instance, we end up handling bogus data in a swtich.
   Clearly something is wrong in such cases and we better abort
   rather than overwritting data silently (and unpredictibly)

Signed-off-by: Kamen Mazdrashki <kamenim@samba.org>
emsmdbp_object: hard-abort when get no PidTagChangeNumber during *_create_folder() call

The clearly indicates that the calling function is not completely
implemented - we should abort imediately (and implement the caller)

Signed-off-by: Kamen Mazdrashki <kamenim@samba.org>
emsmdbp_object: hard-abort in *_open_folder() when parent folder is not Mailbox or Folder

Those are the only parent type we have internally.

Signed-off-by: Kamen Mazdrashki <kmazdrashki@zentyal.com>
emsbdbp_object: soft-abort in emsmdbp_folder_open_table() when why try not-implemented yet table type

Signed-off-by: Kamen Mazdrashki <kmazdrashki@zentyal.com>
emsbdbp_object/*_folder_open_table: Return empty table when caller request unsupported
ype of table to be opened

Signed-off-by: Kamen Mazdrashki <kmazdrashki@zentyal.com>
emsbdbp_object/*_table_get_row_props: hard-abort if we get impossible object type

Signed-off-by: Kamen Mazdrashki <kmazdrashki@zentyal.com>
emsbdbp_object/*_folder_commit_creation: soft-abort if we cant' connect with backend

It may be a temporary failure. Or most probably we are trying
to create not-support folder. In any case we shold not
abort() the process here, rather than that just handle the error.

Signed-off-by: Kamen Mazdrashki <kmazdrashki@zentyal.com>
emsbdbp_object: Handle error which folder_commit_creation() may return

Signed-off-by: Kamen Mazdrashki <kmazdrashki@zentyal.com>
emsbdbp_object: Fix error handling for emsmdbp_object_get_properties()

Signed-off-by: Kamen Mazdrashki <kmazdrashki@zentyal.com>