Fix ee_compat_check when EE branch uses a prefix

Signed-off-by: Rémy Coutable <remy@rymai.me>

lib/gitlab/ee_compat_check.rb

@@ -98,10 +98,11 @@ module Gitlab
       if status.zero?
         @ee_branch_found = ee_branch_prefix
-      else
-        _, status = step("Fetching origin/#{ee_branch_suffix}", %W[git fetch origin #{ee_branch_suffix}])
+        return
       end
+      _, status = step("Fetching origin/#{ee_branch_suffix}", %W[git fetch origin #{ee_branch_suffix}])
+
       if status.zero?
         @ee_branch_found = ee_branch_suffix
       else