Issue:
------
While using the LOAD statement to insert data into an
updateable view, the check to verify whether a column
is actually updatable is missing.

Solution for 5.5 and 5.6:
-------------------------
For a view whose column-list in specified in the LOAD
command, this check is not performed. This fix adds the
check.

This is a partial backport of Bug#21097485.

Solution for 5.7 and trunk:
---------------------------
For a view whose column-list is specified in the LOAD
command, this check is already performed. This fix adds the
same check when no column-list is specified.