gn2bp: Update the condition for genrule_headers

Some genrules generate .h files and other files.
It might be better to split genrules to header genrule and other
genrule.
But, for now, adding module to genrule_headers if the output contains .h
files.

Test: ./update_results.sh
Change-Id: I9ee964f76c60075fa8db04fb383aea7eea3be4ae