Avoid org tree retrieval race condition on patron app

Avoid org tree retrieval race condition on patron app

Avoid calling egOrg.ancestors() during startup, because the org unit
tree is not guarantee to be available until startup has completed.  This
was causing an occasional JS excpetion in the patron app pages, which
prevented the pages from loading.

The error in question:

 TypeError: Cannot read property 'map' of undefined
    at Object.service.get (https://host/js/ui/default/staff/services/org.js:21:25)
    at Object.service.ancestors (https://host/js/ui/default/staff/services/org.js:34:28)
    at Object.egCore.env.classLoaders.actsc (https://host/js/ui/default/staff/circ/patron/app.js:41:37)
    at https://host/js/ui/default/staff/services/env.js:77:55
    at Object.r [as forEach] (https://host/js/ui/default/staff/build/js/angular.min.js:7:290)
    at Object.service.load (https://host/js/ui/default/staff/services/env.js:76:17)
    at https://host/js/ui/default/staff/services/startup.js:64:23
    at J (https://host/js/ui/default/staff/build/js/angular.min.js:101:96)
    at https://host/js/ui/default/staff/build/js/angular.min.js:102:259
    at h.$eval (https://host/js/ui/default/staff/build/js/angular.min.js:113:32)

Signed-off-by: Bill Erickson <berickxx@gmail.com>