Faulty error message is returned when CREATE TABLE fails to create
the table or other object in NDB. For example the error
"Table 'x' dosen't exist" may be returned. This patch
changes the implementation to return the NDB error as a warning
and then setting a "Can't create table 'x'" error in most cases.
Thus it should be possible for the user to figure out what went
wrong by using SHOW WARNINGS after a failed CREATE TABLE.

The problem is caused by the generic mapping tables inside the
NdbApi which are used by ndb_to_mysql_error(). It's not possible
to fix the problem by changing the mapping tables since how to
map an error code depends on the context which the function failed.
For example a "No such table" error may make sense for an INSERT but
not for a CREATE TABLE.

The error handling in ha_ndbcluster::create() is extracted into a
helper class in order to eliminate duplicated boiler plate code
as well as allowing some automatic verification of the behavior
when an error is returned.

The default behavior is that at least one warning should be pushed
together with the error, but for a few cases where the error is
descriptive enough, it's allowed to be returned without any prior
warning.

When an error occurs this is the steps that should normally be done:
1) Push the NDB error or other description of the actual error
   that occurred as a warning.
2) Report the error "Can't create table '<table_name>'" or
   "Can't create destination table for copying alter table" if the
   table is created as part of copying ALTER TABLE.

Exceptions to the above steps are done for errors which occur
due to illegal or missing create options detected, which have
error coded that are specific enough to be set without any preceeding
warning. But, it's allowed (and possible) to push more descriptive
warnings also for those errors. The end goal should be that it's easy
for the user to figure out the cause of the error by using SHOW WARNINGS.

Change-Id: I980b7bed234f2fc3acf8c39545f0e68f87e628a9