Make clearer use of the check.

app/helpers/issues_helper.rb

@@ -16,7 +16,7 @@ module IssuesHelper
   def url_for_project_issues
     return "" if @project.nil?
 
-    if @project.used_default_issues_tracker? || config_issues_tracker?
+    if @project.used_default_issues_tracker? || !external_issues_tracker_enabled?
       project_issues_path(@project)
     else
       url = Gitlab.config.issues_tracker[@project.issues_tracker]["project_url"]
@@ -28,7 +28,7 @@ module IssuesHelper
   def url_for_new_issue
     return "" if @project.nil?
 
-    if @project.used_default_issues_tracker? || config_issues_tracker?
+    if @project.used_default_issues_tracker? || !external_issues_tracker_enabled?
       url = new_project_issue_path project_id: @project
     else
       url = Gitlab.config.issues_tracker[@project.issues_tracker]["new_issue_url"]
@@ -40,7 +40,7 @@ module IssuesHelper
   def url_for_issue(issue_iid)
     return "" if @project.nil?
 
-    if @project.used_default_issues_tracker? || config_issues_tracker?
+    if @project.used_default_issues_tracker? || !external_issues_tracker_enabled?
       url = project_issue_url project_id: @project, id: issue_iid
     else
       url = Gitlab.config.issues_tracker[@project.issues_tracker]["issues_url"]
@@ -60,8 +60,12 @@ module IssuesHelper
     end
   end
 
-  def config_issues_tracker?
-    return false if Gitlab.config.issues_tracker && Gitlab.config.issues_tracker.values.any?
+  # Checks if issues_tracker setting exists in gitlab.yml
+  def external_issues_tracker_enabled?
+    if Gitlab.config.issues_tracker && Gitlab.config.issues_tracker.values.any?
       true
+    else
+      false
+    end
   end
 end