create-diff-object: reduce verbosity in debug mode

With the inclusion of the debug sections, the debug output is so verbose
that it becomes less useful.

This commit reduces the verbosity by skipping rela listings of debug
sections.

It includes a new helper function, is_debug_section(), to consolidate
the logic for detecting debug sections.

Signed-off-by: Seth Jennings <sjenning@redhat.com>
Ah, got it.