dwarf2.c remove varinfo and funcinfo sec field

dwarf2.c remove varinfo and funcinfo sec field

The "sec" field in these structures is only set and used in lookup
functions.  It always starts off as NULL.  So the only possible effect
of the field is to modify the return of the lookup, which was its
purpose back in 2005 when HJ fixed PR990.  Since then we solved the
problem of relocatable object files with the fix for PR2338, so this
field is now redundant.

	* dwarf.c (struct funcinfo, struct varinfo): Remove "sec" field.
	(lookup_symbol_in_function_table): Don't set or test "sec".
	(lookup_symbol_in_variable_table): Likewise.
	(info_hash_lookup_funcinfo, info_hash_lookup_varinfo): Likewise.