Correction of issue using gitlab credential with system scope (#234)

Author: Turiok

src/main/java/io/jenkins/plugins/gitlabserverconfig/servers/GitLabServer.java

@@ -11,8 +11,6 @@
 import hudson.Util;
 import hudson.model.AbstractDescribableImpl;
 import hudson.model.Descriptor;
-import hudson.model.Item;
-import hudson.model.ItemGroup;
 import hudson.security.ACL;
 import hudson.security.AccessControlled;
 import hudson.util.FormValidation;
@@ -243,30 +241,15 @@ public PersonalAccessToken getCredentials(AccessControlled context) {
         Jenkins jenkins = Jenkins.get();
         if (context == null) {
             jenkins.checkPermission(CredentialsProvider.USE_OWN);
-            return StringUtils.isBlank(credentialsId) ? null : CredentialsMatchers.firstOrNull( lookupCredentials(
+        } else {
+            context.checkPermission(CredentialsProvider.USE_OWN);
+        }
+        return StringUtils.isBlank(credentialsId) ? null : CredentialsMatchers.firstOrNull( lookupCredentials(
                                                                                                     PersonalAccessToken.class,
                                                                                                     jenkins,
                                                                                                     ACL.SYSTEM,
                                                                                                     fromUri(defaultIfBlank(serverUrl, GITLAB_SERVER_URL)).build()
                                                                                                 ), withId(credentialsId));
-        } else {
-            context.checkPermission(CredentialsProvider.USE_OWN);
-            if (context instanceof ItemGroup) {
-                return StringUtils.isBlank(credentialsId) ? null : CredentialsMatchers.firstOrNull( lookupCredentials(
-                    PersonalAccessToken.class,
-                    (ItemGroup) context,
-                    ACL.SYSTEM,
-                    fromUri(defaultIfBlank(serverUrl, GITLAB_SERVER_URL)).build()
-                ), withId(credentialsId));
-            } else {
-                return StringUtils.isBlank(credentialsId) ? null : CredentialsMatchers.firstOrNull( lookupCredentials(
-                    PersonalAccessToken.class,
-                    (Item) context,
-                    ACL.SYSTEM,
-                    fromUri(defaultIfBlank(serverUrl, GITLAB_SERVER_URL)).build()
-                ), withId(credentialsId));
-            }
-        }
     }
 
     /**