Change updateNeeded function isUpdateNeeded
Change updateNeeded function isUpdateNeeded

Previously the function was checking if an update was needed then performed the
update. It was not clean. Now it returns an object telling if an update is
needed and if permissions changed.

lemelon/cozy-home,babolivier/cozy-home,jsilvestre/cozy-home,clochix/cozy-home,frankrousseau/cozy-home,lemelon/cozy-home,frankrousseau/cozy-home,clochix/cozy-home,jsilvestre/cozy-home,babolivier/cozy-home