Makefile: Add platform as env var to poste2e test

This exports a variable for the post e2e tests. This variable specifies
the current platform which will be used to detect if the corresponding
component test we are running is supposed to be run on that platform or
not.

Signed-off-by: Suraj Deshmukh <suraj@kinvolk.io>

Makefile

@@ -90,7 +90,7 @@ endif
 run-e2e-tests:
 	KUBECONFIG=${kubeconfig} go test -mod=$(MOD) -tags="$(platform),e2e" -covermode=atomic -buildmode=exe -v ./test/...
 	# Test if the metrics are actually being scraped
-	KUBECONFIG=${kubeconfig} go test -mod=$(MOD) -tags="$(platform),poste2e" -covermode=atomic -buildmode=exe -v ./test/...
+	KUBECONFIG=${kubeconfig} PLATFORM=${platform} go test -mod=$(MOD) -tags="$(platform),poste2e" -covermode=atomic -buildmode=exe -v ./test/...
 	# This is a test that should be run in the end to reduce the disruption to other tests because
 	# it will delete a node.
 	KUBECONFIG=${kubeconfig} go test -mod=$(MOD) -tags="$(platform),disruptivee2e" -covermode=atomic -buildmode=exe -v ./test/...