Show error message received from server side

When an error occurs during authorization, display the error message
received from server side instead hardcoded message.

Partially resolves openbmc/openbmc#2974
Resolves openbmc/openbmc#3024

Tested: Enter invalid username or password and verify error message
Change-Id: I91ca29d5a69e12e12ce490ce3206173de7d41f09
Signed-off-by: Alexander Filippov <a.filippov@yadro.com>
diff --git a/app/common/services/userModel.js b/app/common/services/userModel.js
index f82c1f1..43437c5 100644
--- a/app/common/services/userModel.js
+++ b/app/common/services/userModel.js
@@ -22,8 +22,15 @@
                                 || response.status === undefined)){
                             sessionStorage.setItem('LOGIN_ID', username);
                             callback(true);
+                        }else if(response && response.data && response.data.data
+                                 && response.data.data.description){
+                            callback(false, response.data.data.description);
+                        }else if(response && response.message){
+                            callback(false, response.message);
+                        }else if(error){
+                            callback(false, 'Server unreachable');
                         }else{
-                            callback(false, error);
+                            callback(false, 'Internal error');
                         }
                     });
                 },