WebSession: fix missing default precached value
WebSession: fix missing default precached value

inveniosoftware/invenio-accounts,tiborsimko/invenio-accounts,inveniosoftware/invenio-accounts,inspirehep/invenio-accounts,tiborsimko/invenio-accounts,inspirehep/invenio-accounts,tiborsimko/invenio-accounts,inveniosoftware/invenio-accounts,inspirehep/invenio-accounts