Instead of only aborting hook functions if a handler returns `EVENT_CONSUMED`,
only continue abortable hooks if a handler returns `OK`. For existing core
plugins, this shouldn't make any difference because none of them use the `ERROR`
return value.
Also rename `shouldAbortOnConsumedEvent` to better match the new conditional.
Signed-off-by: Michael Richters <gedankenexperimenter@gmail.com>