Fix some error messages being shown as untranslated

The translations for these strings were not being shown even when they had
been translated. The problem was the trailing space character which had got
dropped by the translation tools. Hence, the translation key in
translations.js didn't match exactly the one given to
gettextCatalog.getString().

js/app/controllers/maincontroller.js

@@ -185,8 +185,8 @@ function ($rootScope, $scope, $timeout, $window, ArtistFactory,
 				reason = response.status;
 				break;
 			}
-			OC.Notification.showTemporary(
-					gettextCatalog.getString('Failed to load the collection: ') + reason);
+			const errMsg = gettextCatalog.getString('Failed to load the collection:');
+			OC.Notification.showTemporary(errMsg + ' ' + reason);
 		});
 
 	};

js/app/controllers/views/radioviewcontroller.js

@@ -69,8 +69,8 @@ angular.module('Music').controller('RadioViewController', [
 				},
 				function (error) {
 					station.busy = false;
-					OC.Notification.showTemporary(
-							gettextCatalog.getString('Failed to delete the radio station: ') + error.status);
+					const errMsg = gettextCatalog.getString('Failed to delete the radio station:');
+					OC.Notification.showTemporary(errMsg + ' ' + error.status);
 				}
 			);
 		}

js/app/controllers/views/settingsviewcontroller.js

@@ -170,8 +170,8 @@ angular.module('Music').controller('SettingsViewController', [
 									},
 									function(error) { // error handling
 										$scope.collectionResetOngoing = false;
-										OC.Notification.showTemporary(
-												gettextCatalog.getString('Failed to reset the collection: ') + error.status);
+										const errMsg = gettextCatalog.getString('Failed to reset the collection:');
+										OC.Notification.showTemporary(errMsg + ' ' + error.status);
 									}
 								);
 						};
@@ -208,8 +208,8 @@ angular.module('Music').controller('SettingsViewController', [
 								},
 								function(error) { // error handling
 									$scope.radioResetOngoing = false;
-									OC.Notification.showTemporary(
-											gettextCatalog.getString('Failed to reset the radio stations: ') + error.status);
+									const errMsg = gettextCatalog.getString('Failed to reset the radio stations:');
+									OC.Notification.showTemporary(errMsg + ' ' + error.status);
 								}
 							);
 					}
@@ -238,8 +238,8 @@ angular.module('Music').controller('SettingsViewController', [
 								},
 								function(error) { // error handling
 									$scope.podcastsResetOngoing = false;
-									OC.Notification.showTemporary(
-											gettextCatalog.getString('Failed to reset the podcast channels: ') + error.status);
+									const errMsg = gettextCatalog.getString('Failed to reset the podcast channels:');
+									OC.Notification.showTemporary(errMsg + ' ' + error.status);
 								}
 							);
 					}