set RSPECQ_ENABLED=1 when using use-rspecq commit flag; refs DE-822

test plan:
-set use-rspecq commit
-verify env var RSPECQ_ENABLED=1

Change-Id: I923cd7abc67535ffd5d38d09e7492320c27c760a
Reviewed-on: https://gerrit.instructure.com/c/canvas-lms/+/273712
Reviewed-by: James Butters <jbutters@instructure.com>
Tested-by: Service Cloud Jenkins <svc.cloudjenkins@instructure.com>
QA-Review: Kyle Rosenbaum <krosenbaum@instructure.com>
Product-Review: Kyle Rosenbaum <krosenbaum@instructure.com>

build/new-jenkins/library/vars/rspecStage.groovy

@@ -262,6 +262,7 @@ def runReporter() {
 
 def useRspecQ(percentage) {
   if (configuration.isRspecqEnabled()) {
+    env.RSPECQ_ENABLED = '1'
     return true
   }