Update more types for section index change

Commit f89276a2 ("change type of `general_symbol_info::m_section`
to int") did what it says in the title -- changed the type of the
section index from short to int.  However, it seems incomplete, in
that there are uses of the section index that use the type 'short'.

This patch fixes the ones I found, first by searching for
"short.*sect" and then by looking at all the callers of section_index
(and then functions called with the resulting value) just to try to be
more sure.

Approved-by: Kevin Buettner <kevinb@redhat.com>
Approved-By: Simon Marchi <simon.marchi@efficios.com>