Fix assorted rspec failures due to stale, cached user permissions

RequestStore is disabled in tests, but the Ability class was
caching user permissions based on the user and project ID of
previous test runs. Revise code to use RequestStore only if it
is active.

app/models/ability.rb

@@ -166,38 +166,44 @@ class Ability
     end
 
     def project_abilities(user, project)
-      rules = []
       key = "/user/#{user.id}/project/#{project.id}"
 
-      RequestStore.store[key] ||= begin
-        # Push abilities on the users team role
-        rules.push(*project_team_rules(project.team, user))
+      if RequestStore.active?
+        RequestStore.store[key] ||= uncached_project_abilities(user, project)
+      else
+        uncached_project_abilities(user, project)
+      end
+    end
 
-        owner = user.admin? ||
-                project.owner == user ||
-                (project.group && project.group.has_owner?(user))
+    def uncached_project_abilities(user, project)
+      rules = []
+      # Push abilities on the users team role
+      rules.push(*project_team_rules(project.team, user))
 
-        if owner
-          rules.push(*project_owner_rules)
-        end
+      owner = user.admin? ||
+              project.owner == user ||
+              (project.group && project.group.has_owner?(user))
 
-        if project.public? || (project.internal? && !user.external?)
-          rules.push(*public_project_rules)
+      if owner
+        rules.push(*project_owner_rules)
+      end
 
-          # Allow to read builds for internal projects
-          rules << :read_build if project.public_builds?
+      if project.public? || (project.internal? && !user.external?)
+        rules.push(*public_project_rules)
 
-          unless owner || project.team.member?(user) || project_group_member?(project, user)
-            rules << :request_access if project.request_access_enabled
-          end
-        end
+        # Allow to read builds for internal projects
+        rules << :read_build if project.public_builds?
 
-        if project.archived?
-          rules -= project_archived_rules
+        unless owner || project.team.member?(user) || project_group_member?(project, user)
+          rules << :request_access if project.request_access_enabled
         end
+      end
 
-        rules - project_disabled_features_rules(project)
+      if project.archived?
+        rules -= project_archived_rules
       end
+
+      rules - project_disabled_features_rules(project)
     end
 
     def project_team_rules(team, user)