workload-automation: fix AEP configuration regex

WA v2 and WA v3 use different variable names for installing
plugins/extensions. This enables using both v2 and v3 syntaxes for AEP.

Change-Id: I6e2408918baa1a773c71df9984b57c4e43ced63f
Signed-off-by: Milosz Wasilewski <milosz.wasilewski@linaro.org>
2 files changed