Makefile: Explicitly specify GINKGO_OPTS for the e2e/olm target

Update the root Makefile and extend the e2e/olm target to explicitly
configure the ginkgo options that gets filtered to the
staging/operator-lifecycle-manager e2e target that was introduced in [1].

[1] operator-framework/operator-lifecycle-manager#2367

Signed-off-by: timflannagan <[email protected]>

Author: timflannagan

Diff for: Makefile

@@ -122,7 +122,7 @@ e2e/operator-registry: ## Run e2e registry tests
 	$(MAKE) e2e WHAT=operator-registry
 
 e2e/olm: ## Run e2e olm tests
-	$(MAKE) e2e WHAT=operator-lifecycle-manager
+	$(MAKE) e2e WHAT=operator-lifecycle-manager "GINKGO_OPTS := -flakeAttempts 3 -randomizeAllSpecs -v --timeout 120m"
 
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