Add usage disclaimer for spec file.

Author: pvalena

ci/rubygem-abrt.spec

@@ -1,4 +1,6 @@
-# Generated from abrt-0.0.2.gem by gem2rpm -*- rpm-spec -*-
+# THIS SPEC FILE IS AN OUTDATED COPY OF FEDORA ONE. USE IT ONLY FOR CI.
+# https://src.fedoraproject.org/rpms/rubygem-abrt/blob/master/f/rubygem-abrt.spec
+
 %global gem_name abrt
 
 Name: rubygem-%{gem_name}