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>
No, but it looks like it :)  Before, the code only checked text sections by matching ".debug_".  is_debug_section() handles both text and rela sections.  So the debug rela sections will now get inside the conditional and there is no reason to use the ->rela indirection from the text section.