Bump template version for all templates to "ocata"

Bump template version for all templates to "ocata"

Heat now supports release name aliases, so we can replace
the inconsistent mix of date related versions with one consistent
version that aligns with the supported version of heat for this
t-h-t branch.

This should also help new users who sometimes copy/paste old templates
and discover intrinsic functions in the t-h-t docs don't work because
their template version is too old.

Change-Id: Ib415e7290fea27447460baa280291492df197e54