Revert "Return Environment from validate_template"

validate_template return format was changed in Queens release, which causes testsi
verifying this API call to fail.

Reverting the change allows failing tests to pass on Pike.

Change-Id: I4906b93282be3e93f2047db6db4a913ed6502b36
Closes-Bug: https://mirantis.jira.com/browse/PROD-19199
2 files changed