Events: crash with procedure which alters events with function
Post-review CS
This fix also changes the handling of KILL command combined with
subquery. It changes the error message given back to "not supported",
from parse error. The error for CREATE|ALTER EVENT has also been changed
to generate "not supported yet" instead of parse error.
In case of a SP call, the error is "not supported yet". This change
cleans the parser from code which should not belong to there. Still
LEX::expr_allows_subselect is existant because it simplifies the handling
of SQLCOM_HA_READ which forbids subselects.
Introduced EVENTS.EVENT_DEFINITION, like ROUTINES.ROUTINE_DEFINITION
Hence, the contents of the current EVENTS.EVENT_BODY become the contents
of EVENT_DEFINITION. EVENT_BODY will contain always, for now, "SQL" (wo
quotes).
