relocate the entry point address when used

This changes the entry point to be unrelocated in the objfile, and
instead applies the relocation when it is used.

2014-01-15  Tom Tromey  <tromey@redhat.com>

	* objfiles.c (entry_point_address_query): Relocate entry point
	address.
	(objfile_relocate1): Do not relocate entry point address.
	* objfiles.h (struct entry_info) <entry_point>: Update comment.
	<the_bfd_section_index>: New field.
	* symfile.c (init_entry_point_info): Find the entry point's
	section.