fix(service): fix lost of data in async loader / error in runtime
fix(service): fix lost of data in async loader / error in runtime

Accidently, a promise handler for loading translations transform the data into `undefined` internally resulting into type/npe at runtime.

Relates #1471

DWand/angular-translate,angular-translate/angular-translate,DWand/angular-translate,angular-translate/angular-translate,DWand/angular-translate