Complying with ISO 8601, don't omit the [T]

These events are useful and the timestamp is critical. Please don't change the standards. The rest of salt code does this correctly. If you need it for readability I suggest taking the event and emitting a log message with the format you wish to view it or tell your application reading the event to change the standard into non-standard.
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ISO 8601:2004(E): ISO. 2004-12-01. "4.3.2 NOTE: By mutual agreement of the partners in information interchange, the character _[T] may be omitted in applications where there is no risk of confusing a date and time of day representation with others defined in this International Standard._
Merge pull request #11099 from bretep/patch-4

Complying with ISO 8601, don't omit the [T]